


A Study in Love

by Rearviewdreamer



Series: A Study in Love (Sherlock au) [1]
Category: One Direction (Band)
Genre: Crime Scenes, Detective Louis, Doctor Harry, M/M, Sherlock AU, Strangers to Lovers, serial killer mystery
Language: English
Status: Completed
Published: 2018-01-24
Updated: 2018-02-13
Packaged: 2019-03-08 19:21:23
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 6
Words: 24,305
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13464873
Author URL: https://archiveofourown.org/users/Rearviewdreamer/pseuds/Rearviewdreamer
Summary: Louis knows everything about everyone which has put him at a great and weird advantage over nearly all of them since the very beginning. He can solve any puzzle before most people know where to begin. He is rarely perplexed, mistaken, or wrong, and obviously, Louis is never ever surprised. And yet, his new flatmate after a very long string of failed ones has Louis questioning how he ever did any of it without him.





	1. Chapter 1

**Author's Note:**

  * For [larrysunrays](https://archiveofourown.org/users/larrysunrays/gifts).



_Wednesday. 4:06am. 221b Baker Street. London._

The thin strings of Louis’ violin cut into the pads of his fingers as he plucks his way up the neck of the instrument to hold the focus of his mind in one place. The question at hand is a vexing one that has haunted him since he was a child. He mumbles to himself, idly playing the notes to Dvorak’s Concerto in A minor without the use of a bow but the answer still evades him, lost in the web of thoughts that seems to be growing by the second, as well as the awful racket his flatmate is making rummaging around like a rat in the night.

“Could you keep it down? I’m thinking,” Louis says from his armchair, reconsidering his previous hypothesis as his fingers fill the room with a symphony of flat, staccato notes. Maybe if he played them correctly he’d have more success with his mental debate. “Actually, could you hand me my bow?”

“Um, no?” his flatmate snaps. “I told you I’m moving _out_. Weren’t you listening?”

Vaguely, however it wasn’t intentional. He grabs the bow himself from the floor, allowing it to drag across the strings. “Could always go for the bolder taste, though,” Louis answers himself. “Yes, bold. Even just the word incites vigor, energy, _power_.”

“You’re not listening,” his flatmate pipes up again, nearly causing Louis to lose grip on his rapid train of thought. “Though, I’m not at all surprised.”

“ _Shh!_ Stop talking. Yes, potency is key, however, the bitterness often associated could leave something to be desired. Perhaps the lighter, then?”

“You’re fucking _insane_. I hope you know that,” Anthony rudely interrupts again, walking into Louis’ line of vision in front of the open window to grab the shriveled little cactus sitting on its ledge. “I’m taking this with me since _you_ never water it. And for the love of god, would you _please_ stop playing that damn violin!”

He stomps back the way he came until the music screeches to a halt and Louis’ left arm suddenly swings out in front of him with the instrument in hand, just inches from his crotch.

“ _No_ ,” he gasps, meeting Anthony’s stunned gaze with an enlightenment Louis thought he’d never get to know. This is groundbreaking. “No, no, no, no. Earl Grey is too _light_. It’s too delicate; too sweet, meaning it’s merely releasing endorphins and tricking the brain into thinking it’s good,” he realizes, wondering why it has taken him almost thirty years to come to that conclusion. “Tartness is what gives a good tea its _edge_ ; its _bite,_ Anthony. It’s what people love most about it, or at least the competent ones anyway, therefore, Yorkshire truly is the best. Full stop,” he grins proudly.

“You’re out of your fucking mind,” Anthony scoffs before sidestepping his violin.

No Louis isn’t. He just single-handedly solved the greatest dispute in the history of morning time beverages.

“Where are you going? Do you have any idea what bloody time it is?” Louis frowns when he notices all the boxes congregated by the door.

“Yes, I know exactly what time it is. That’s what I’ve been trying to tell you! It’s four in the morning and you’re sitting in front of an open window in your pants, playing violin, and going on about fucking tea of all things.”

“Yeah, I’m not really understanding where the bad is in the extremely basic observation you just made.” Open windows open the mind, clothing hinders blood flow, music soothes the soul, and tea only makes the bloody world go ‘round. In Louis’ opinion, this has already been a highly productive day and the sun’s not even up yet.

“The bad is that I can’t do this anymore. I can’t live here with you in this madhouse with your creepy murder cases lying about and all your jars full of eyeballs and other weird shit all over the place including _my_ room.”

“Those are for experimental purposes and also, they add to the décor.”

“They’re disgusting, weird, and I’m done looking at them. It’s been nice knowing you.”

“Stop being dramatic. I get it. You’re not a morning person and you’re upset, but I can make you a cuppa if that’ll help smooth things over. I was just about to make one for myself anyway,” Louis shrugs before Anthony starts dragging his things out into the corridor. 

“Don’t even bother,” he grunts with the effort. “I despise Yorkshire.”

And that’s all Louis needs to hear to know that this flatmate-ship was never going to work out. “You’re right. We’re totally different people,” Louis agrees on his way to the kettle. “Leave the key with Mrs. Hudson downstairs.”

 

_Wednesday. 10:34am. 221b Baker Street. London._

“Hello, Lottie.” Louis greets his sister from the comfort of his kitchen, knowing it’s her rudely busting into his flat without even having to pop his head out of the room. “To what do I owe the grand pleasure?”

Her quick steps freeze just on the outskirts of the living room, becoming sparse and uneven as she carefully makes her way through the minefield of shit lying out to get to him.

“This place looks terrible,” she says, stopping dead in her high-heeled tracks with a hand clasped over her heart when she reaches the kitchen and notices the samurai sword being wielded through the air. “ _Louis_ ,” she gasps. “What the hell are you doing in here?”

“Making a salad of course,” he explains as he draws the sword back and lets it swing onto the head of lettuce on the table. “Would you like one as well? I can always chop up some extra.”

“Don’t you dare swing that again!” she warns just as the blade comes down on another giant chunk of vegetable. “You couldn’t use a regular knife and cutting board like a normal person?”

“No. Sounds dreadfully boring.”

“Is _this_ why Anthony left in such a fit this morning? Mrs. Hudson said he was livid. Were you seriously in here waving that sword around like a crazy person?”

“No, I wasn’t doing anything this morning! I was simply making tea. The _normal_ way with a kettle and all. I’m not a barbarian,” he sighs when Lottie raises a doubtful eyebrow. “Anthony was just so oversensitive, Lotts. It was never going to work anyway. And plus, he smelled weird.”

“Yeah, it’s called soap,” she quips. “You should try it sometime. And, that’s exactly what you said about the last flatmate you had.”

“Maybe that’s because I don’t _need_ a flatmate. I’m not a child.”

“Could’ve fooled me,” Lottie scoffs as she takes in the state of the place. “Someone has to keep an eye on you, and besides that, you can’t even afford this place on your own. You have to split the rent.”

“For your information, I am paid very well for my services and this flat is well within my salary.”

“Yes, it is. Except you rarely accept anyone’s payment, and when you do, you spend it all on tea and fucking samurai swords.” She’s got a point there, iterating it even more when she crosses the room to snatch the artifact out of his hands. “I’m finding you another flatmate, Louis, and this one had better last longer than a month or I swear.”

“Yeah, yeah. I know. You’ll kick me in the balls or do something else that lacks imagination.”

“I can shove this sword up your arse. How’s that for imagination?”

The likelihood of her actually doing it is far greater than Louis’ willing to bet at the moment, and her wide grip around that sword says she means business.

“Er- Right, then. I’ll behave. Second flatmate’s the charm.”

“This will be your third.”

“…Right. My mistake. _Third’s_ the charm,” Louis concedes as he stretches to reach the hatchet ax on top of the fridge to finish preparing his meal to his sister’s great dissatisfaction.

“ _LOUIS!_ ”

 

 _One week later._ _1:33pm. 221b Baker Street. London._

“Now, he’s not the tidiest person in the world, but he’s hardly ever home whenever he’s working so he’ll be out of your hair for the most part.”

Harry aims a kind grin at the woman he was fortunate enough to meet yesterday morning in the café after another day of fruitless flat hunting.

“That’s alright. I don’t mind a little chaos. It’s nothing I can’t handle,” he assures Lottie, receiving the same polite, yet anxious quirk of her lips that she gave yesterday when she found him hunched over his phone reading the classifieds, and said she knew of a newly available room for rent that wasn’t listed.

“A little chaos,” she echoes with a nervous chuckle that tapers off into silence. “ _I sure hope you’re right about that,”_ Harry thinks he hears her mutter as they start up the stairs to the second floor but he can’t be sure. “Um, I forgot to ask before, but are the steps going to be a problem for you?” she checks when she notices him taking twice as long as her to climb them.

“Shouldn’t be. I’m sure I can manage. I’ve definitely seen worse,” he chuckles back, working to hide the small limp he got as a souvenir working in Afghanistan for the past year.

They stop in front of door 221b and Harry already likes the look of the place and the sound of the soft violin music seeping into the corridor. Perhaps this could be home after all.

“Now, he doesn’t get many visitors and he’s not a fan of surprises so I told him I’d be by today,” Lottie warns.

“That’s okay,” Harry nods. “I’ve always been kind of quiet too.”

“Quiet…right,” Lottie says with another nervous chuckle to herself before leading the way inside the flat.

The moment the door opens Harry is hit with the scent of old books and the spring breeze wafting through the open window across the room. It’s a cozy little flat covered in printed wallpaper and mix-matched furniture that reminds Harry of the house his grandparents used to live in. The shelves against the walls hold just as many tea cups as books and every surface in the room seems to be covered in either police reports or sheet music. A few things make Harry raise an eyebrow like the random specimen jars scattered around and the bullet shells littering the floor. The place is a mess just like Lottie said as his eyes scan over it, but so far, it’s nothing too- “Is that an ax?”

Lottie follows his gaze to the blade stuck in the wall near what looks to be the kitchen but doesn’t confirm or deny before kindly coaxing Harry a little further into the flat behind the armchair facing the window that seems to be producing the beautiful melody Harry heard from before.

“Lou?” Lottie addresses the back of her brother’s head. “There’s someone I’d like you to meet. This is Harry.”

Louis gives no indication of hearing her introduction so Harry gives it a go. “Hi there,” he tries, though his attempt gets about the same reaction.

“So, Louis,” Lottie continues. “Harry’s a doctor from-”

“Yes. I know where he’s from,” Louis sighs, as he plays one last note to end his piece but doesn’t make an effort to stand or turn around. “He’ll do.”

“Wait. How?” Harry feels his face screw up at such a declaration. “We literally just met. You don’t know anything about me.”

“Oh, now I wouldn’t say that,” Louis counters. “I know loads. Precisely everything I need to, like the fact that you’re from Manchester but you didn’t stay there very long after you were able to leave judging by the slightly watered-down quality of your accent. Your family’s still there though. They must be, otherwise you you’d just stay with them instead of seeking out a flatmate.”

“Er- Yeah. Spot on,” Harry frowns at the armchair. “That’s amazing.”

“Not really. Just a simple observation,” Louis says before continuing on. “Just like the fact that you rely heavily on your left leg. You put most of your weight on it when you walk, however the sole of your left shoe hasn’t been worn down by it, implying either new shoes or a new injury, however, if you’re in need of someone to help split rent, you wouldn’t buy new shoes so it must be the latter. But, where would a young doctor from Manchester acquire such a traumatic injury to his right leg that’s still fresh enough to cause discomfort, yet not old enough to wear down your soles? My first guess would be military frontlines, but you don’t strike me as the type, so my second guess is Doctors Without Borders.”

All Harry can do is blink at the back of this man’s head with his jaw hanging open in astonishment. “That’s actually completely right,” Harry confirms. “I did a year with DWB in Afghanistan before I got injured. Just got back.” He hasn’t even had time to tell Lottie half of those things about himself and yet her brother just figured them out in under three minutes.

“There’s more,” Louis informs him. “Not only are you a selfless, life-saving, adrenaline junkie of a doctor, but you’re also quite attractive or else my sister wouldn’t have doused herself in perfume before coming here or bothered with clacking around in a pair of new heels that haven’t been properly broken in yet, which is highly unfortunate for her.”

“Why’s that?” Harry asks, utterly fascinated as Louis stands to face him for the first time; all blue eyes and a self-satisfied smirk accentuated by a week’s worth of chestnut-colored stubble.

“Because, I fear her efforts are wasted judging from the almost two-foot distance between the two of you, meaning you’re either not interested, already taken, or the most likely option, gay.”

“ _Incredible_ ,” Harry marvels in conjunction with Lottie’s unimpressed, ‘ _Why are you always such a know-it-all prick_?’

“Harry, I’m so sorry. I really wish I could say this is out of character for him,” she apologizes just as a phone begins to vibrate and Louis sprints across the room to snatch it up from the window ledge.

“Come on, London, don’t let me down,” he mumbles as he opens his new message. “I’ve been stuck in this bloody flat for days. Just give me another serial killer. Or a regular killer. _Anything_ worth my while.”

Harry tears his gaze away from Louis to find Lottie pinching the bridge of her nose with her eyes squeezed shut. “Did he just say-?”

“THANK GOD!” rings out from the window, startling Harry half to death and causing Lottie’s eyes to fly open just to roll them with a weary shake of her head. Louis shoves his phone into the back pocket of his jeans and then begins pulling on pieces of clothing better suited for work than a hoodie. “Well, Lotts, don’t just stand there in your glossy pumps. Get the man his new key,” he says as he grabs a dark coat from the rack by the door with an open collar. She produces a small silver set from her bag and hands them over to him.

“Wait. I’m moving in?” Harry frowns after several beats.

“Well, aren’t you?” Louis raises an impatient brow. “You coming?”

Once again, Harry’s brain takes a few seconds to catch up with Louis’. “W-Where exactly?” he asks making his new flatmate sigh at him on the way out the door.

They hop into the back of the first cab they see and Louis rattles an address along with very specific directions for the driver about the route to get them there.

“So, which is it? Don’t keep me in suspense,” Louis says to someone, though Harry’s not really sure who since he’s idly scrolling through his phone.

“Er- Me?”

“Well, yes, you. Who else?” A pair of sky-blue eyes lock on Harry and suddenly it’s impossible to mistake who Louis is speaking to. “As I pointed out, you didn’t take the bait with my sister, so, which is it?”

Harry feels his brow furrow in amusement at such a simple inquiry from a man who just summarized his entire life without so much as a glance. “You mean, you can’t guess?”

“First of all, I never _guess_. I simply pay attention,” Louis ensures him. “And, of course I already know. I just didn’t want to assume.”

“Well, obviously, your sister is a very kind and beautiful woman,” Harry admits. “She also has impeccable taste in shoes.”

The whisper of a grin appears at the corners of Louis’ lips, but it happens so fast that Harry can’t really be sure. “Say no more, my friend. I hear you loud and queer,” he answers making Harry bite down on a grin of his own. “So, Harry,” Louis says after returning his attention back to his phone. “Us living together was a bit… _sudden_. Any burning questions? If I can’t answer them, I’m sure Mrs. Hudson can. You’ll love her by the way.”

Harry doesn’t really have any questions about the flat. It’s a roof over his head and it won’t cost him half as much as the other places he looked at. The only questions he has are all related to his flatmate who is unlike any other person Harry has ever met.

“I can’t wait to meet her. And to figure you out,” he shrugs. “We’re practically strangers, but that won’t take long to fix. After all, I pay attention too.”

 _“Right_ , mate,” Louis chuckles to himself as their car pulls to a stop outside a tall building of flats. “Of course you do.”

*

The first thing Louis notices about the rundown building he’s standing outside of are the dozens of officers milling about his crime scene and his new flatmate who doesn’t seem to be following him to the entrance.

“You coming?” he asks for the second time today. Harry blinks at him in surprise like he didn’t expect to be invited along for this part of the trip.

“Oh. Erm…I don’t know?” he asks in what was clearly a statement. _That’s_ going to get annoying fast. “I didn’t think I was allowed. I just figured I’d-”

“Nonsense. You’re with me,” Louis says, but Harry doesn’t exactly hurry to join him after another glance around at all the officers swarming the grounds. “Or just stay out here,” he shrugs. “I mean, there is a bloody serial killer on the loose, but whatever you prefer.”

His flatmate gives it a few second’s thought before making his way over to Louis with a slight limp, which at a distance, seems to have no true origin.

“Interesting.”

“Hmm? What is?” Harry asks with a furrowed brow as they continue inside the building together.

“Nothing. Nothing at all,” Louis shrugs.

They follow the trail of police up to a flat on the fourth floor that is absolutely teeming with them when they arrive.

“Alright! Everybody out!” he says, which works to clear the majority of the people away from the crime scene, minus a few stubborn people who simply roll their eyes.

“Oh, Jesus,” Nick grumbles to someone from across the room. “Who the hell called _you_?”

“Someone who obviously wanted this case solved right, now get out,” he quips back.

“ _Case_? There is no case. It’s a suicide. Clearly, ‘someone’ misinformed you,” Nick scoffs. “And, who is that?” he frowns to Louis’ left at the man watching their exchange in confusion.

“Don’t worry about it. He’s with me.”

“With you how?” Nick snorts. “What, like a partner? That’s impossible. You don’t even know how to work with other people.”

“I know how to ring your wife on the business trip she’s away on and ask how she managed to give you that poorly concealed love bite under your jaw and make it back to America so fast.”

“Who told you my wife was away?”

“No one. If she were in town and she gave you the love bite you wouldn’t have bothered covering it, so you must be keeping it secret for some reason. And, also, that concealer is two shades too dark for your skin, however, _Melissa_ has been wearing it for years and it’s masking the matching love bites on her neck perfectly.” Nick falls silent at that as he turns to Melissa who is determinedly staring at the floor to avoid his eyes. “Now, for the second time,” Louis smiles. “ _Get out_.”

“ _Louis_ ,” a familiar voice gently chastises him from behind as the rest of the people including Nick file out of the room while giving him death glares. “You can’t just make people leave when they’re working. We’ve been over this,” Inspector Payne says as he comes around to face him and Harry still standing wide-eyed to his left. “Who’s this?”

“He’s with me.”

“He doesn’t have clearance.”

“Well, I say he does.”

 _“_ Technically _, you_ don’t even have clearance, Louis. This was ruled a suicide.”

“Oh. Right. Well, since my consulting services aren’t needed, then I’ll just-”

“Now, hold on. I didn’t say that,” Payne whispers with his hands raised in surrender. “I messaged you because _something_ here feels weird. I just can’t place it.”

That sounds promising, coming from him. As much as Louis likes to taunt and torment some of the officers who work in this city, he must admit that every one of them is very good at what they do, especially Liam Payne.

“Show me. Lead the way.” Louis tells him, making sure to pull his adorably uncomfortable-looking flatmate with the superficial limp along as well.

As far as crime scenes go, it’s not the worst one Louis has ever witnessed. There’s no blood at all, thankfully. Just a woman slumped over on a kitchen table next to a half-nibbled meal and a bottle of pills.

“So? What do you think?” Inspector Payne asks after Louis steps back.

“Don’t know. I’m curious as to what he thinks.”

Harry’s eyes raise from where they were respectfully cast down away from the body. “Me?”

“Yes, you. You’re a doctor. You’ve seen a dead body before so you must have some insight. I’d like to hear your thoughts.”

Both Harry and the inspector look at Louis like he has lost it condescending to seek someone else’s advice. And he wouldn’t normally, but something tells him his new flatmate is capable of more than just helping him split the rent.

“Wait. I’m confused. Who is he again?” Payne whispers.

“ _Shh_. _He’s thinking_ ,” Louis admonishes him as Harry makes his way over to the table. He takes his time looking over the body before him, glancing over at Louis with a vaguely lost expression when he reports his findings.

“Erm- An unmarried female. Early to mid-thirties. Overdose. Suicide, though possibly accidental depending on how many pills she took. We’ll have to wait for the tox-screen to know for sure?”

It’s the same shallow conclusion every other person who walked into this dining room came to besides inspector Payne, and understandably so since someone went to so much trouble to make it seem like this woman took her own life.

“Again. But, this time look for the _not_ so obvious.”

“Louis, I’m not a detective. I don’t understand what-”

“Just try it one more time,” Louis encourages him.

His flatmate lets out a frustrated huff before staring down at the body again. It’s not until his eyes travel beyond it that he speaks up. “The pill bottle is nearly full. With a milligram dosage that low, she’d have to have taken at least half.”

“Her plate is also mostly full,” Louis adds helpfully.

“True. It seems like a waste to cook an entire meal with no intention of eating it. Why even bother, you know?”

She wouldn’t have. But, that’s still not the deciding factor that makes this not a suicide.

“What do you notice about her choice of beverage?” Louis asks. “Her wine glass was drained and the bottle is missing about three-fourths of it. Perhaps she just really liked wine?” Louis suggests, stepping up next to him, but Harry doesn’t look convinced as he examines the items a bit closer.

“It’s a nice bottle.”

“Exactly,” Louis agrees, grinning a bit as he practically hears the gears turning in Harry’s head. “A _very_ nice bottle.”

“So nice that it feels out of place in a flat like this… because someone gave it to her?” Harry raises an eyebrow, though mostly at himself for jumping to such an off-the-wall conclusion from nothing more than a fancy merlot label. He looks so hilariously surprised that Louis forgets to be annoyed at him making questions out of statements again. “But who?” he frowns, unable to piece the rest together just like Inspector Payne before him who could sense something was off.

“My guess would be the same miserable person who joined her for dinner at the other side of this table.”

Louis’ words cause both men to furrow their brows as they look in that direction and see nothing indicating another person having been here. He makes a show of clearing his throat for the big reveal, almost giddy as he presents the missing pieces of this puzzle.

“That’s a fresh wine stain in front of the other chair that’s the same size as the rim of her glass.” It’s faint and blends in seamlessly with the other small nicks and stains in the light-colored wood, but it’s there. She wasn’t alone. “Check the cabinets. There should be a squeaky-clean, fingerprint-less wine glass in one of them. The killer would’ve wanted to be thorough. And check the garbage as well. There’s probably a whole plate’s worth of food sitting at the bottom of it.”

There is indeed a freshly polished glass amongst the others when Inspector Payne goes to check. There’s also an immaculate dinner plate with blue flowers around its edge that looks completely unsuspicious until Louis points out that it’s part of a four-piece set but it was carelessly stacked with another set that looks nothing like it. There is no food in the bin, which only leaves one other sickening alternative.

“What happens now? Now that they know she was killed?” Harry asks after Inspector Payne has the other officers come back to collect what evidence is left and the body has been removed.

“Now, we wait for whoever did this to do it again,” Louis answers, already trying to think ahead of this person to where and when it’s going to take place.

Harry looks immensely troubled by the thought of this happening a second time, but his emerald eyes also look hopeful that it won’t. “W-Well, maybe he won’t kill again. Maybe this was just a horrible accident.”

“No. He ate the food,” Louis explains, making Harry’s frown deepen. “If it were accidental, any _normal_ person would’ve panicked and left or at least called for help. They definitely wouldn’t have had the stomach or appetite to stick around, but he did. He sat here and finished his dinner in front of a dead body. He’s a psychopath, Harry. A relatively smart one at that, and what’s worse is he now thinks he’s invincible so this won’t be the last time he tries it. Not even close.”

“And…I take it you’re _not_ worried about a potential serial killer on the loose,” Harry concludes after a moment of studying the determined set of Louis’ jaw and that gleam of excitement in his eyes that he feels every time he gets called into a case like this.

“No. Because I’m smarter, he’s going to fuck up, and I’m going to catch him.”


	2. Chapter 2

_Sunday._ _2:29pm. ~~221b Baker Street. London~~. The Twilight Zone._

Harry reaches beneath the old leather sofa in his new living room as far as he can, hoping against hope that whatever the hell he pulls from its depths won’t make him regret the decision to tidy up like the random bone he found a few seconds ago which he sincerely hopes belonged to a chicken at some point. His fingers brush along something oddly skin-like and Harry immediately snatches them back to dig his phone out of his pocket. It’s not as bad as he thought when he shines the light on it and his fingers close around a folded-up leather pouch filled with an assortment of…throwing knives?

Realization dawns on him as he sits up on the floor, now able to identify the peculiar blade-shaped holes pierced through the wall paper near the window close to the bullet-shaped holes in the wall next to it. The fact that his flatmate apparently uses their home for target practice is a bit concerning, though not nearly as much as the giant samurai sword he walked in on Louis using yesterday morning to slice an avocado. _Nude._

The throwing knives are probably better off remaining lost under the sofa where they can do no more harm, but Harry arranges them on the bookshelf next to the daggers he found in the pantry and the three antique pistols he recovered from between various seat cushions; all of them thankfully unloaded. Usually, Harry isn’t one for violence and weapons and that sort of thing, especially after working in war zones for year and witnessing their devastating effects, but in Louis’ case, he knows these items mean something different. They’re like toys to him. Bizarre little trinkets he has accumulated over the years that he values more than any expensive watch or sports car he could own instead. From what Harry can tell, he uses most of this stuff including the violin to clear his mind and help him think, so really, it’s all harmless. Just like him.

Louis’ unique set of eccentricities were obvious the moment Lottie introduced them and have only gotten more apparent as time goes on, but they’re not _bad_ per se, and Louis’ honestly not the raving lunatic people perceive him as. Admittedly, he is a little quirky. And crazy, but in a cool, mad-scientist kind of way, and an exceptionally brilliant one at that. Louis is hands-down the most interesting person Harry has ever met, which is why he often laughs to himself whenever Louis looks at him like _he’s_ the weird one… Kind of like right now as the door knob turns, Louis steps through the front door of their flat, and he freezes right where he is on their freshly-vacuumed floor.

“You’re back.” Harry greets him with a smile that Louis doesn’t rush to return as his quick eyes catalogue every small modification Harry has made to the place in his absence. He has taken it slow with moving his things in this week; a few medical books on a shelf here and his record player on a table top there. A gentle easing-in process at the advice of Louis’ sister that has gone fairly unnoticed. Until now.

“The curtains. You replaced them,” Louis says after a long silence that makes Harry wonder if his spontaneous spring cleaning session was something he should have run by Louis first since change clearly isn’t his thing.

“Er- No, no, not at all,” Harry hurries to assure him. “These are the same ones. I just washed them.” In Louis’ defense they look like new curtains now that the thick layer of dust has been removed from them revealing a beautiful soft green. He offers Louis another small smile as a peace offering, biting down on it when Louis’ gaze falls to the clean carpet beneath their feet that’s virtually unrecognizable now that it isn’t covered in an ocean of sheet music and case files.  

“Um. So, funny story. I ran into Mrs. Hudson of all people this morning who very casually mentioned some cleaning supplies downstairs so, you know, I just thought I’d do a bit of tidying up today. B-But nothing too major, of course. Everything’s still here,” he promises, earning nothing but more silence in return. “I stacked all your work things on the desk in chronological order and your sheet music in alphabetical order by composer. I figured that’d make the most logical sense since all your books are ordered that way by author.”

His respectful consideration while handling Louis’ prized possessions appears to have been the right choice so he keeps talking.  

“I cleared a shelf to make space for all your knives and guns to be displayed. Um, I also noticed a few jars stashed around the flat that seem pretty important like the, erm, _eyeballs_ , so I placed them all together as well on the mantel here. And, since you seem to love the fresh air from the window so much, I figured you wouldn’t mind if I added a few living things to the décor like a few houseplants to balance out some of the dead things like your skull painting and the human ear I found in the freezer a few days ago. Which is lovely. Just, you know, _severed_.”

Louis glances at the new leafy additions scattered around the room and then audibly sniffs the air, unable to locate the source of the flowery aroma filling his lungs.

“Oh. Er- Scented candles,” Harry offers helpfully. “Midnight Orchid Breeze.”

The thick silence between them right now makes Harry glad all the weapons are on _his_ side of the room.

“My chemical flasks?” Louis asks after a beat.

“Kitchen. In the cupboard next to the tea mugs,” Harry happily reports.

“There were bullet shells next to the sofa...”

“Yes, and no worries because they’re all right here in this cute little bowl. All twenty-six of them,” Harry grins as he picks it up to rattle them around as proof.

“… _Right_ ,” Louis comments when he’s unable to find fault with anything here. He looks quite impressed with Harry’s efforts. Harry would daresay he looks almost _pleased_. Is that a smile?

“Everything’s okay, right?”

“ _No_.”

“N-No?”

“No. Because nobody else seems to think it strange for the toxin level indicator to be almost three times that of the expected level from missing medication. I mean, honestly, do I really have to think for _everyone_ working in this city or is it just the people who refuse to accept numbers and facts as indisputable, concrete evidence?”

“Oh,” Harry says realizing that they’re now talking about something completely different from bullet shells. “You mean your case. Um, that is rather odd. I’m sorry.”

“So am I,” Louis answers. “And the answer to that by the way is, yes _, I do_. So, let’s go.”

His flatmate grabs Harry’s jacket from the coat rack and tosses it in his direction. Harry stumbles to catch it before it hits ground, his weak leg wavering as it bears the brunt of his weight.  

“G-Go?” Harry frowns as Louis turns and quickly starts down the stairs of their building. “But, I’m cleaning. And, you just got here!”

“And now we’re leaving. I need a lab,” Louis shouts back. _We? “_ And stop doing that with your leg. There’s nothing wrong with it.”

Wait. _What?_

Harry quickly slips on his jacket and runs to blow out the candle he bought so they still have a flat to come back to when they get back. “What the hell are you talking about?” Does Louis think he’s faking the bullet that went through his thigh? All he receives in answer is an exasperated, _‘It’s psychosomatic! Now, hurry up!’_ as Harry locks their door behind him and hurries to catch the cab his flatmate just jumped into the back of.

 

 _Sunday._ _2:56pm. St. Bartholomew Hospital._

“What do you mean it’s all in my head? Haven’t you been listening?”

Louis sighs as he holds open the car door for his flatmate, already bored of answering the same question over and over. “I meant exactly what I said. You don’t have a limp. You _had_ a limp. Past tense. Now, your leg is perfectly fine.”

He watches Harry’s face twist up in offence and imaginary pain as he overexerts his stronger leg to follow him up the hospital steps.

“Lead with your right leg then,” Louis says suddenly, making Harry stop halfway and scoff aloud. “No, seriously. Go on and prove me wrong. Walk up these stairs putting pressure on your injured leg and tell me with a straight face that it hurts you.” Harry laughs at him again like the request is ridiculous. But, after a few seconds tick by, he looks more curious to try it than annoyed at Louis for suggesting it in the first place.

He gives a petulant sigh, rolling his eyes at Louis and himself before standing up straight and firmly planting his right foot on the next step. He holds his breath as his weight bears down on it to swing his left leg onto the step after that and then blinks up at Louis with wide green eyes.

“Well? Are you dying? Are you in excruciating pain? Are the blades of a thousand knives stabbing you?”

Harry rubs his fingers over the scar tissue hidden beneath the right leg of his jeans with a frown.

“…Not really?” he answers after experimentally pressing down on it a few times. Louis doesn’t even bother boasting as he watches his flatmate confidently tackle the remaining steps without so much as a grimace, too busy admiring the amazed disbelief on Harry’s face to say _I told you so_. There’s still a slight discrepancy in the strength of his muscles from lack of good use of course, but that’s nothing that can’t be fixed with a bit of time and patience. His flatmate looks thrilled as he comes to the same conclusions.

“It doesn’t hurt at all actually,” Harry grins when he reaches the top. “I can’t believe you were actually right. Amazing.”

Within about five minutes of knowing Louis, most people tend to become very bored of that trend. They become disillusioned with Louis’ personality and vice versa, so he has never been very good at making and keeping friends or flatmates for that matter. Yet, for some reason, it seems that Harry has only come to admire him and respect him more as they get to know each other better. And strangely enough, Louis fears the sentiment goes both ways.

“Well, I try not to make a habit of being wrong very often,” Louis smirks as he holds the door to the hospital open for Harry to walk through. “Get used to it.”

As soon as they arrive at the autopsy wing Niall Horan lets out a long sigh which Louis chooses to interpret as wild excitement upon seeing him.

“Niall, my sunshine! I’ve missed you.”

“You do know you can’t just break in here whenever you feel like it, yeah?”

“ _Break_ in?” Louis scoffs. “Who says I ever break in? Obviously, there’s a code to unlock the door.”

“Yeah, _my_ code. For _me_ , the person who actually works here,” Niall deadpans before standing and forcing Louis into a hug that feels more like a choke-hold as Louis tries and fails to escape it.

“ _I hate it when you do this!_ ” he groans with his face turned as far away from Niall’s as physically possible.

“Oh, I know. That’s exactly why I do it.” Niall stops being annoying as fuck after a while and lets him go, only then noticing the second person currently trespassing on his domain. “Oi, who’s this?”

“He’s with me,” Louis answers, brushing himself off and readjusting his coat collar. “Anyway, I’m looking for a woman,” he says ignoring Niall’s mumbled ‘ _Really?_ _That’s a first,’_ and Harry’s poorly concealed snort afterwards. “A _dead_ one. She was brought here two days ago. She was poisoned. Where is she?”

“Oh, yeah. You mean the woman who overdosed,” Niall corrects him as his curious eyes trail Harry walking around, politely inspecting the tools and instruments surrounding them.

“ _No_. Poisoned. That’s exactly what I’m here to prove.” Louis digs into the pocket of his jacket for the samples he smuggled out of evidence this morning while visiting Inspector Payne.

To Louis’ surprise, Niall surrenders his lab without much more of a fuss. By now he has probably learned that it’s simply easier to cave early rather than sit through another painstakingly detailed deduction of exactly where he’s been, what he’s been doing, and who he’s been doing it with. Granted, Louis only does that when Niall is being particularly stubborn about sharing his shiny, state-of-the-art toys. Or, whenever Louis’ made to cuddle against his wishes.

“By all means, Louis, just hijack my work station. It’s not like I was using it or anything.”

“Cheers, mate. Thanks,” Louis smiles after he hip-checks Niall out of the way to compare the toxin sample from the body with the crime scene samples he stole from earlier with the best microscope in the city.

It only takes a second to confirm what Louis already knew when he examines each sample side by side. “Harry! Come look at this.” His flatmate jumps at being addressed so suddenly and then winces when the frontal lobe of the model brain he was just examining clatters to the ground.

“Who is he again? And why is he destroying my lab?” Niall whispers as Harry quickly repairs the model with a faint blush on his cheeks. “Jesus, he’s as bad as you.”

“Aw, now that’s not true,” Louis smirks. “No fire alarms are ringing. There hasn’t even been an explosion.”

“ _Yet_ ,” Niall rolls his eyes, stepping around to the opposite side of the table so Harry can be next to the microscope.

“Here, Harry. Sit down and tell me what you see.” Louis relinquishes his seat for him and Niall’s eyebrows shoot up towards his hairline. Harry expertly adjusts the dials a bit until the images clear up for him and then his eyebrows are also shooting up.

“They’re different toxins. Two of them, I think. The medication was in her system when she died, but obviously, that’s not what killed her? It was the other one.”

He only made one statement/question during that whole deduction and he came to that conclusion so quickly that Louis almost feels doubly triumphant.

“ _Precisely_ ,” he confirms with a wicked grin. “You’re exactly right! I mean, sure you’ve missed almost everything of importance just like everyone else, but still. Nice job, mate.”

“Wait, _who_ is he again?” Niall demands for the billionth time only to be ignored again.

“Niall, shut up. The bigger and more pertinent question here is why this woman was poisoned with Tetrodotoxin and where her killer even got it from since it’s highly illegal.” Both Niall and Harry blink at each other with blank expressions as Louis remembers not everyone has read _Weidenborner’s Encyclopedia of Toxicology_ from cover to cover. “It’s the substance found in Fugu,” he explains, only to sigh because apparently no one else knows Japanese either. “Honestly, what do you people do all day? You know, a Pufferfish? Big, ugly, prickly thing that’ll kill you if eaten incorrectly?”

“ _Ohhh. Those,”_ Harry says at the same time Niall proclaims he knew that all along and then mutters that he thinks pufferfish are kind of cute.

“Uh, no, they’re kind of _deadly._ The fish itself is completely banned in most countries including its poison.” It’s not something that can just be picked up at a local shop. “The killer had to have gotten it from someone in Asian black market retail, but it wouldn’t be advertised. No, not a poison like this,” Louis thinks aloud. “It’d have to be stored someplace inconspicuous; hiding in plain sight. Accessible to the highest bidder, but also kept under lock and key...”

“Like… the restricted section of the Asian fusion shop I visited this morning that’s right around the corner from ours?”

Louis blinks over at Harry and frowns at the same time Niall’s face screws up.

“ _Our_ s?”

“I’m serious, Louis,” he continues over Niall’s outburst. “There was this entire room in the back that no one was allowed to go in. It was sectioned off as restricted with all these weird little bottles of stuff on the shelves, but I just figured they were herbs and spices. I didn’t ask questions.”

“Wait. You mean to tell me you just happened upon an underground black market shop off of Baker Street in search of bloody house plants and candles?”

Harry just shrugs. “Maybe. I like bonsai trees. I wanted some small ones for the flat, so, I went and found some.”

“You mean to tell me you two _live_ together?” Niall exclaims. “Jesus, you poor thing,” he laments with a consoling squeeze to Harry’s forearm. “I know he’s had flatmates in the past but I’ve never actually _met_ one of them in the flesh. My God,” he breathes in awe. “What’s it like?”

“Oh, fuck off, Ni.” Louis pulls his right leg back to kick the shit out of him under the lab table when Harry’s soft chuckling stops him.

“I hate to spoil the mystery, but it’s not that bad at all,” he promises with a playful nudge to Louis’ side. “Actually, it’s been pretty great so far. I think we get on quite well. Right, Lou?”

Louis blinks in surprise at the nick name, accustomed to only hearing it from his sister. “Er-” He hadn’t expected any of the kind things Harry said, and definitely not the way Harry’s bright smile temporarily disarms him and muddles his thoughts when it has certainly never done that to him before. “Erm, yeah. I-I think we do.” Harry looks more than pleased to hear that, the result of which forces Louis to grin back at him through the bizarre little spasms currently rolling through his stomach. Must’ve been all the tea he had before.

Niall looks between them with a new regard akin to someone witnessing a miracle. “And I think Hell’s freezing over. Go figure,” he quips.

The sound of Louis’ pocket vibrating prompts his stomach to finally settle down and for Harry to return his gaze to the slides beneath his lens.

“Well, I don’t know if the shop I found is really where the killer got this stuff, but we could always go check it out since it’s close. Someone there must know something,” Harry suggests just as Louis pulls up his new message from Inspector Payne.

“You’re right. We should investigate, but it’ll have to wait.”

Something about his tone causes Harry to glance up from the microscope.

“It’s happened again, hasn’t it?” he asks quietly though the grave expression on his face says he already knows the answer. Louis knew it would only be a matter of time before it did happen again, and although Harry didn’t want to admit it initially, deep down he must have known it too.

“I can have the taxi drop you at home if you’d rather sit this one out,” Louis tells him as he pockets his phone and stores his samples in Niall’s lab for safe keeping. He’s sure he’ll be back for them soon enough with samples from this new crime scene as well.

“That’s okay. I’ll be fine. And, besides that, you shouldn’t go alone.”

“Well, it’s kind of my job so I don’t mind going by myself.”

Louis has been a one-man act since day one. Dragging his new flatmate along as a tourist was fun while things were relatively quiet, but this case won’t stay that way for long.

His flatmate nods his understanding, but isn’t swayed. “Yeah, I know,” he shrugs. “Still doesn’t mean you should. I’ll come if you don’t think I’ll be too much trouble.”

Harry isn’t any trouble at all. He’s literally the opposite of trouble, never once getting in Louis’ way. He’s also an adult who can make his own choices, so Louis doesn’t argue when he determinedly stands to follow him out of the room.  

“Good luck, you two!” Niall calls after them. “Remember the lab’s here if you need anything else.” Louis smirks over his shoulder at him and Niall quickly amends his invitation. “For _scientific_ purposes only. Do bullshit experiments and blow shit up at yours.”

“ _Niall_ ,” Louis gasps. “As a fellow man of science and a respected member of the community, I am offended.” His last experiment was conducted solely for scientific purposes, and now, his brain encompasses a very extensive list of items that _don’t_ enjoy being doused with a mixture of acetone peroxide and sulfuric acid.


	3. Chapter 3

_Two days later._ _6:36am. 221b Baker Street. London._

The latest homicide in this growing case didn’t really tell Louis anything he didn’t already know about the brand new fanatic running wild through the city. Everything about the crime scene was nearly identical to the first, featuring an unsuspecting victim poisoned in her own home where even the same expensive brand of merlot showed up. Even Officer Nick was there annoying the living shit out of everyone, making the whole scenario feel a bit like déjà vu. The only difference was the lack of evidence of a second place setting this time around, and also the fact that this second victim’s flat was so much nicer than the last, meaning not only is the killer learning, but showing off.

Catching him won’t be difficult once Louis is able to piece it all together and track him down. With two victims killed in the exact same way, Louis has a definite M.O. to work with. It’s no coincidence that two women on opposite ends of the city were home alone before he murdered them without forcing entry, so there _is_ a correlation. Louis can’t see it yet, but it’ll come to him eventually. In the meantime, the sun’s rising, his duvet is getting hot, and there’s a fresh box of Yorkshire tea waiting for him in the kitchen and nothing in the world clears his head better than that.

Louis kicks out of his sheets and stretches even though his restless mind woke him well over an hour ago. Sleep never comes easy during a case which is even more motivation to solve it quickly, and also, to enjoy a good cuppa in his armchair. He tightens his robe around his waist as he steps out of his bedroom, careful to miss the creaky part of the floor so as not to disturb his flatmate who has enough trouble sleeping as it is from nightmares that Louis assumes are a byproduct of working in warzones for a year. A completely wasted effort on his part it seems when Louis walks into the living room to find Harry already up and about and doing downward facing dog of all things in the tiniest pair of black shorts known to man.

His knees are slightly bent as he holds it, the weak muscles of his right leg clearly feeling the strain when he slowly comes out of it and transitions to cobra and then pigeon pose. He breathes in deep as a soft breeze filters in through the window cooling his sweaty skin. Louis doesn’t move with his gaze fixed on all the places it shouldn’t be when Harry senses he has an audience and glances over his shoulder.

“Oh, hey. Good morning,” he grins, the corners of it turning into a small wince as he comes out of his last pose to turn and face him.

“Morning,” Louis replies perhaps a bit too slow when a tiny crease forms between Harry’s eyebrows. “So… sunrise yoga,” Louis begins without any real plan of where he’s going with it, only realizing he’s staring again when his brain keeps looping the image of Harry squeezing into those damn shorts this morning. “Impressive.”

“Eh, not really,” his flatmate shrugs. He stands up from his mat and Louis immediately averts his eyes someplace other than the dark trail of hair disappearing into the waistband of the infamous thirty-two inch, size small athletic shorts with light stitching at the seams and polyester drawstring that’s been frayed in the wash after approximately two years of use; but, that’s just an estimate. “I used to do yoga all the time before I got hurt, so I figure it can help me get my strength back in my injured leg and- and what exactly are you looking at over there?” he asks, following Louis’ determined gaze to the blank spot on the wall behind him.

“Nothing. Nothing at all,” Louis answers much quicker than last time. Too quick apparently, earning him another confused look. “I-I was going to make some tea, so I’m just gonna-”

“Oh, I was going to make some anyway when I was all done in here, so I can get it,” Harry suggests, which is very considerate of him, but tea is not a game. It’s serious fucking business; a process, and Louis refuses to drink it in any way that lacks absolute _precision_.

“Er- That’s incredibly kind of you, Harry, but I’m afraid I’m just a bit particular about certain-”

“Yeah, I know,” Harry grins. “Relax. I’ve got it.”

Louis watches him leave the room with actual fear gripping his heart wondering what horrors his precious Yorkshire might endure at the hands of a man who peels his bananas bottom first.

“W-Watch the temperature,” he calls after him. “A-And don’t let it steep for too long.”

“I won’t,” Harry chuckles from the kitchen. “And I know you take it with milk, but just a splash. No sugar, and you prefer it tea bag in.”

Louis’ chest relaxes a bit, taking comfort in his flatmate’s general knowledge of how to treat a cuppa right. It won’t be perfect. Louis isn’t foolish enough to hope for that, but from the sounds of it, he’ll at least be able to choke it down so as not to hurt Harry’s feelings.

*

It has been nearly a whole minute without either of them saying a word when Harry starts to wonder if he really did fuck this up somehow without meaning to.

“Louis? Is there something the matter?”

The rich sky-blue of Louis’ eyes is the first thing Harry sees when he blinks up from the mug in his hands.

“This is the single best cup of tea I have _ever_ had,” he admits, giving life to the triumphant smile that spreads across Harry’s face. “Holy shit, it’s perfection. How? How did you create this utter masterpiece?”

By watching Louis like a fucking hawk each time he has so much as filled the kettle. His extreme attention to detail in terms of just heating it was definitely on the neurotic side, but it also made Harry smile to know he takes tea so seriously. His flatmate takes another blissful sip and everything from the quiet sigh he makes to the way his eyelashes fan out over his cheeks makes every second of the tedium worth it.

“I told you before. I pay attention,” Harry brags, laughing when Louis agrees wholeheartedly with a quick succession of nods. “Well, you seem like a satisfied customer so I’ll leave you to it, yeah?” He collects his own mug to go return his yoga mat to his bedroom and change, but he hardly makes it two steps away before his flatmate speaks up.

“Thank you, Harry.”

That almost makes Harry smile as much as his initial reaction to the tea. “Of course, Lou. Don’t mention it.”

“You don’t have to run off just because I’m in here. I think we can probably manage drinking our tea in the same room.” It’s not a direct invitation, but it’s probably as much of one as Louis could extend without outright asking Harry to stay. Harry realized pretty early on that Louis enjoys his space, but sometimes, as seldom as it may occur, he also enjoys being with people, and right now is clearly one of those times.

“You think so? Okay, we’ll try it,” Harry answers as he places his mug down to roll out his mat again. He settles down in the center of it right next to Louis’ armchair and his violin giving him a beautiful view of the city lighting up with early sunshine. “Just let me know if I’m annoying you somehow.”

“You’re not. And you won’t.”

“Well, still. And I mean let me know with _words,_ not your throwing knives,” Harry teases. “I can take a hint.”

“I’d never throw things at you. Especially not knives,” Louis assures him. “It’d be much less work to just use the sword. Or at least one of the guns.” There’s a wide grin visible on Louis’ face when he takes another sip of his tea that has Harry smiling into his mug as well.

“I guess I better behave then,” he jokes back.

Assuming Louis _was_ just joking of course.

*

The rest of their morning passes just as peacefully as the start of it after the sun comes up and their stomachs begin rumbling for more than just tea. There’s a café nearby that, according to Louis, has the best full English in the city, and coincidentally is less than four blocks away from the Asian Fusion shop they finally have time to check out.

The building is just as small and unassuming as it was when Harry happened upon it days ago. Even the dark sign hanging over the door is easy to miss, which is probably why this place has gone virtually unnoticed by everyone, including Louis, for all this time.

“Now, when we get in there I’m just going get a feel for the place. We’re just going to poke around a bit and see what we can find out. Let me ask all the questions.”

“Okay. Got it,” Harry nods.

“Just act natural. Blend in,” Louis tells him. “And, try not to break anything this time.”

Harry rolls his eyes, regretting even touching that brain model in Niall’s lab since he’s never going to live it down for as long as he lives. “Hands to myself. Got it.”

Apparently, that’s assurance enough for Louis who gives a firm nod and squares his shoulders just before stepping through the shop door.

The warm scent of orchids fills Harry’s lungs the moment he walks in, instantly putting him at ease the way it did the first time he came here and ended up buying half the candles on the shelf. He casually floats through the shop looking at all the items displayed for sale, staying mindful of the restricted section in the back as well as the employee dutifully hovering next to it to make sure no one gets too curious; signs and red flags that Harry paid zero attention to a few days ago. However, Louis isn’t as oblivious as he was. In fact, he only pretends to be interested in the oil paintings Harry is admiring for a moment before snatching one from the wall and heading up to the register with it.

“Will this be all?” the man behind the counter asks as he rings it up.

“Yes, and also a few ounces of your best Tetrodotoxin you have lying around,” Harry’s flatmate replies, silencing the entire shop within a millisecond. “It’s kept hidden in the back isn’t it?” he pushes. “I mean, it must be otherwise you wouldn’t have just glanced over there, unknowingly revealing its exact location, nor would you suddenly look quite so panicked about housing an illegal substance in the first place.”

The man behind the counter vehemently denies any such knowledge which only exasperates Louis further as it does any time he knows he’s right about something, which just so happens to be all the time.

“You know, between you and me, I’ve never really understood the point of lying,” Louis sighs. “Especially when someone is awful at it. It’s not your fault of course. Most people on this Earth _are_ terrible liars. They should just stick to the truth. Like, for instance, just being honest about supplying Tetrodotoxin to whoever has the cash to pay for it.”

The man behind the register doesn’t respond well to being accused of lying or of selling illegal goods. He looks about two seconds from throwing Louis out of the shop which wasn’t at all the goal here. They’ll leave with nothing if that happens so Harry disobeys Louis’ direct instructions to ‘blend in’, to try his luck instead.

“Er- Please excuse my colleague here. What he _meant_ to say is that we’re both professors teaching a toxicology course to the medical students at St. Bartholomew tomorrow and we heard around the hospital that you might be able to help us gather some rather sensitive resources we can’t just order online. It’s just a quick demonstration-type thing on some earthworms, but it’ll help our students tremendously if you’re able to help us out.”

Harry offers the man his kindest smile making Louis gawk at him like he’s just grown an extra head.

“Erm. Yeah...” Louis nods. “What he said. My _colleague_.”

The salesman seems less anxious and suspicious the longer Harry talks, eventually admitting to storing the poison in the back of the shop, and also agreeing to sell it, but _only_ to him. Louis, he’s still not too fond of.

Once they’re out of the shop, Harry passes Louis the little vial he just purchased, frowning when he notices his flatmate’s roguish smirk. Louis tucks the vial into his left coat pocket and pulls a thin leather journal out of his right; the same one the salesman just recorded Harry’s secret purchase into and apparently missed Louis swiping right from under his nose.

“You stole the poor man’s journal?” Harry snorts.

“Of course I did. And now, we have a detailed inventory of every person in the city who has been there looking for Tetrodotoxin. All thanks to you, liar. I mean, _Professor_ Liar,” he corrects. “My apologies.”

Harry can feel his face warming a bit from having Louis be this this impressed with him, but he quickly shrugs it off, accepting his praise with a cool, _‘It was nothing,’_ that only serves to make Louis smile more.

That evening, Harry comes home from the grocery shop to an empty flat. Or, at least, he had assumed it was empty. That was before he found Louis camped out at the kitchen table, still poring over his stolen journal that he hasn’t put down since this morning while looking up anyone who stands out as a potential psychopath.

“Find anyone else suspicious yet?” Harry asks, which just makes his flatmate snort.

“This is a three-hundred-page record of secret black market transactions. _Everyone_ ’s suspicious.” Harry supposes that must be true, chuckling along as Louis reads out the weirdest things people have bought this month alone. After a while, Louis places the journal down with a sigh and squeezes his eyes closed as if the words have started blurring together. “I think it’s time for more tea.”

Harry glances around at the various mugs already lying used around the room, noticing a peculiar absence of used _plates_ to go along with them. “No, I think it’s time for _food_. Have you even stopped to eat anything since this morning?” The guilty chewing of Louis’ bottom lip is answer enough when he sighs again.

“You’re right. I know. I should take a break and go get something.”

“You could. Or you could take a break, save yourself the trouble of going out, and just have spaghetti with me instead,” Harry nods over at the large bag of food he just picked up. “I’ve got plenty.”

“Seriously? You’d do that for me?” Louis frowns like perhaps no one else has ever offered.

“Of course I would. _However_ ,” he grins under the promise of his one condition. “If you want to eat you’ve got to earn your keep. You’re helping prepare and also clean up.” Louis raises an eyebrow at that, but doesn’t seem opposed to the idea of paired cooking. “I’m putting you on chopping duty first. There’s tomatoes, peppers, and onions in the bag.”

“Say no more. I’m already on it,” Louis agrees with a little too much enthusiasm that makes Harry regret not specifying the _type_ of tool he should chop with.

*

By some miracle, their kitchen is still standing nearly an hour later with their pasta complete, a few toasted garlic rolls Harry had the mind to pop into the oven while Louis cleaned off his ax, and two exceptionally large glasses of wine to celebrate their efforts. No sooner do they sit down to enjoy the fruits of all their labor does a light knocking sound on their front door followed by the click-clack of a pair of heels wandering through their flat.

“Lou? Harry?” Lottie calls from their living room, blinking back in surprise when she pokes her head inside the kitchen. “Oh. Er- Hello, boys,” she greets them together, looking almost fearful that she has walked into the wrong flat. “I’m sorry. I was just checking in since I haven’t been by lately. I didn’t mean to interrupt anything.”

“You’re not interrupting at all,” Harry smiles at her. “Have you eaten yet? We started on the wine a bit early, but we’ve still got plenty. You should join us.” Louis’ sister eyes their dinner table with interest, still looking largely unsure until her big brother encourages her too.

“Yeah, Lotts, please? Grab a seat. The more the merrier, like Harry said.”

Her skepticism about such a unanimous request for her company fades after a few seconds of being charmed by her brother’s smile. “O-Okay,” she grins back. “Since you both insist. Dinner actually sounds really nice right now. And that spaghetti smells _really_ good.”

“Thanks. I made it myself,” Louis boasts, amending his bold declaration when Harry flicks a rogue piece of onion at him from across the table. “And Harry helped. A little,” he smirks.

Two large bottles of wine have emptied right before their eyes by the time the three of them realize they’ve been laughing and talking well into the evening and the kitchen isn’t going to tidy itself. Louis holds up his end of the dinner bargain by helping Harry clean up, but it goes much faster with Lottie lending a hand as well.

“Hey, Harry? I’m going to take some of this pasta and bread down to Mrs. Hudson,” Louis informs him when he realizes there’s too much leftover to fit inside the container. “Be right back.”

“Okay,” Harry answers over his shoulder, elbow deep in suds and dish water. “Tell her I say hi.”

The front door closes behind Louis’ promise to do just that. It’s not until Harry hands off another wet plate to his sister that Harry notices the same bewildered grin tugging at her lips that has been there all night.

“What’s so funny?” Harry laughs at her expression.

“Nothing,” she lies, until an unexpected snort gives her away. “I promise it’s nothing, it’s just- watching you two together. It’s just so… so _normal_. It’s _weird_.”

Harry laughs too. He can understand how witnessing a bit of normalcy in this flat might come as a shock to her. Then again, when she showed up tonight, she had just missed Harry’s own private lesson from her brother on ax wielding in culinary arts, so.

“Well, there’s nothing wrong with that, is there?” he checks. It’s not like he has tried to make her brother into something he’s not or vice versa. This is simply the way their lives have slotted together; little pockets of normal wherever they can squeeze them in. 

“No, Harry, not at all. I think it’s fantastic that he finally gets along with someone. The way he was tonight with you though is like nothing I’ve ever seen before. I mean, he cooked a meal with you, made genuine conversation while eating it, and there wasn’t even gunfire involved,” she jokes as she dries the wet dishes that Harry passes to her. “He invited _me_ to stay for dinner which hasn’t happened since we were children. It’s almost like he’s a different person.”

“Tonight _was_ a lot of fun,” Harry admits, hoping it wasn’t just a one-time thing for them.

“When we met, I figured you two wouldn’t kill each other if you moved in here. But, Harry, he actually _likes_ you. He really truly does.” It seems she isn’t the only person shocked by their fast friendship. Nearly everyone they encounter when they’re together reacts the same way.

“Well, it’s mutual because I really like him too.” Louis and all his little quirks are just a few of the many, many things Harry admires about him. “I think Lou’s great and so intelligent sometimes that it’s scary,” he chuckles to himself. “He’s honestly the most amazing person I’ve ever met,” Harry admits with perhaps too much fondness in his voice from the knowing grin Lottie aims down at the drying towel in her hands. “Um. I just- I meant that he and I get on really well, you know?” Harry amends after a clearing of his throat that’s just as incriminating as the faint blush he can feel on his cheeks.

It’s silent between them for a long time before Lottie finally breaks it.

“Harry,” she begins softly, and already, Harry doesn’t like where this is going. “I can tell that you really do like him. And the way he is with you is unlike I’ve ever seen him around anybody else...”

Just hearing that makes Harry feel good. _Special_.

“But?” he pushes, sensing one is coming.

“ _But_ , I think we both know my brother’s a little, well, _different_.” That’s putting it lightly, but sure. They’ll go with that.

“I’d say that’s a pretty fair assessment, yes,” Harry smirks because she’s not wrong.

“And I think the way you feel about him, and that you care for him is wonderful, Harry. I’m just not so sure he’s capable of _returning_ those kinds of feelings. He never has with anyone before as far as I know.” She says it so gently that it almost feels like a letdown. “ _But_ ,” she grins after a moment. “I think it’s also safe to say that if my brother ever were to let someone in, it’d be you.”

That’s not exactly a sure-fire guarantee that he and Louis could have something one day, but it’s just close enough make Harry feel like it isn’t impossible.


	4. Chapter 4

_The next day._ _7:13am. 221b Baker Street. London._

Louis wakes with a small start the way he usually does after accidentally falling asleep in front of the living room window. The cool night breeze wafting in is normally what causes him to stir, but today, warm sunshine is pouring in instead of moonlight, his violin is tucked away in its case, and a dark green blanket that’s usually folded up at the end of Harry’s bed has somehow found its way tucked around Louis’ shoulders.

He feels himself grin from the warmth of the fabric encasing him, thinned a bit from years of use yet heavily perfumed with Harry’s scent for the very same reason. One deep breath in has Louis daydreaming of springtime even in the dead of fall, catching hints of Harry’s shampoo that often lingers in rooms long after he has left them.

The springs of his armchair make a small squeak when Louis finally uncurls himself from the corner of it after realizing he just spent a whole two minutes of his life breathing in a blanket. He stands with it still pulled tight around him though, ready to go return it to his flatmate’s room, however, he hardly even makes it a full step before catching the soft rumble of a snore coming from the sofa and the sight of his flatmate stretched out on top of it.

It was well past midnight once all the suspects from their journal started blurring together, so Louis has no idea what time they actually crashed. After jumping straight from dinner to helping clear over a hundred people from the list, he’s sure Harry was exhausted. Even so, he still managed to outlast Louis, and even made sure Louis didn’t wake up shivering like a human icicle.

Harry falling asleep here wasn’t intentional. That much is obvious from his darkened laptop screen due to low battery and the pencil he was using to take notes sharing the edge of the sofa with him. He’s covered in goosebumps all along his forearms and even the portion of his stomach visible where his t-shirt has ridden up.

This must be exactly the way Harry found him the night before, so Louis returns his gracious favor and drapes the blanket over top of him. Thankfully, Harry doesn’t stir. He merely sighs in his sleep, making Louis chuckle to himself as he nuzzles into the familiar weight of it and then resumes peacefully snoring. Lying this way, Louis would daresay he looks almost sweet. Not at all like the menace he really is who sings pop hits in the shower, organizes food in the fridge by expiration date, and enjoys half-naked yoga at dawn. Not that Louis’ complaining about that last one, or about any of them really; all the hundreds of thousands of interesting little things that make up someone so fascinating, and coincidentally, someone who’s probably going to want a fresh mug of tea when he wakes up rather than the half-full one next to the sofa that’s been cold for hours.

The way Harry takes it is a disgrace of course. A complete and utter bastardization of tea itself, but still, Louis reckons he can at least give it a go. It’s only fair, especially since Harry takes such care with the way Louis likes his. And plus, he hasn’t seen Harry smile since last night before they started working and a big, warm cuppa is sure to put a megawatt of one on his face first thing. At least, Louis hopes so anyway. 

He watches Harry’s tea steep with unease, watching the clock hanging on the wall as it’s second hand makes three revolutions around its face, prompting Louis to do the unthinkable and remove the bag. He tries not think about the blasphemy of it all as he drops 3.125g of perfection into the bin or as he dilutes what remains of the weakened flavor by adding not only milk, but the one substance that should never _ever_ be anywhere near a respectable cup of Yorkshire; sugar. Nevertheless, it’s the way his flatmate likes it so he keeps the grimace off his face as he tiptoes back into the living room with it in hand.

“Harry? Haz, wake up,” Louis whispers next to him, only for Harry to momentarily frown in his sleep which Louis would ordinarily find endearing because it is. Except for a day like today where Louis threw away a perfectly good teabag of Yorkshire to make a mug of sugary water with a dark brown tint. “Harry, the flat’s on fire.”

His flatmate splutters awake at that, sitting upright with wide eyes and the expression of someone who expects to be burned alive at any moment. “ _What’d you say?”_ he pants, his panic dissipating once he notices the glaring absence of actual flames.

“I made you tea. Glad you’re up,” Louis announces, holding off on handing it to him right away until his heart returns to his chest and he can hold it without spilling. Harry releases a relieved sigh, his brow furrowing when he notices the soft blanket covering him that he didn’t put there himself. He immediately looks to Louis, his confusion gone and replaced with newfound understanding and also delighted surprise, creating that weird fluttery feeling in Louis’ stomach that he can’t even blame on caffeine this time.

“You did? For me?” The velvety smooth quality of his voice has always sounded nice to Louis, currently even slower and heavier than usual after such a late night. It’s a lot to take in with the morning sun making his eyes impossibly green and the sentimental expression on his face making Louis feel impossibly warm from the inside out. “Thank you, Lou. That was very thoughtful of you.”

“Oh. Um, not really. It was nothing,” Louis assures him. “It’s just- I never really thanked you for dinner last night and also for helping me with the case. And, I know how you like a cuppa first thing and then I saw you sleeping here with no tea so I just thought that maybe I’d, erm…” Louis lets his words taper off once he realizes he’s rambling. Which is nothing new in his case. Rambling is oftentimes responsible for Louis’ greatest breakthroughs, but that sort of endless thought pattern usually makes sense and leaves Louis feeling enlightened. This? Louis doesn’t know what the hell this is or why Harry has done nothing but grin since he realized they weren’t going to die in a fiery blaze. Perhaps Louis has underestimated the man’s fondness for tea. And for him.

He only gets to witness Harry take one sip from his mug before the simultaneous vibration of their phones interrupts the moment, but even with that small taste, Harry seems quite pleased and incredibly flattered.

“It’s Liam. He says it’s urgent,” Louis relays once he walks over to where his phone was resting on top of his violin case instead of on the floor where it usually ends up during the night.

“I got the same message,” Harry reveals as he reads over his phone too. “I hope no one has been hurt when we get there.” Louis isn’t at all surprised by Harry’s optimism. At this point, he has come to expect it as well as admire that about his flatmate. However, it is interesting to him that Harry has thrown himself so far into this case with him that they get matching distress texts. “What? Shouldn’t we get going?” he asks in the midst of searching for his shoes when he notices Louis just standing there blinking at the word _we._

“Nothing. You’re right. We should hurry.” Louis heads off in search of his own shoes and also his coat, trying to stamp down on his wildly inappropriate grin because unlike Harry, Louis knows that someone somewhere is a lot more than just hurt for Liam to say it’s urgent. But, at the same time he can’t help it because he’s never had a partner before.

*

Louis could tell something was different the moment their cab pulled onto Sterling Street. There were too many stricken faces. Too many officers leaving the flat building with hard sets to their jaw, revealing either disgust about whatever has happened that they couldn’t prevent, or most likely, anger. Louis understands both emotions when he arrives at a sectioned off flat and the first thing he notices are random shards of glass left behind on the floor from the result of yet another fast and careless clean-up by their killer.

“Careful,” Louis whispers, holding onto Harry’s arm when he almost walks right over it, distracted by the all the other tell-tale signs of a struggle surrounding them. What interests Louis is that there are no signs of forced entry to go along. This person waltzed right in, or rather, was invited just like the two times before and then somehow disappeared without being noticed, leaving behind another body for somebody’s loved ones to discover later. Wherever that may have been this time because it obviously wasn’t the empty kitchen that Louis can see into from where he’s standing. It’s somewhere in the flat, though. He can smell blood in the air. 

“Thanks for getting here so quick,” Inspector Payne greets him wearing a grave expression just like the other people currently milling about.

“Of course. What do we know?”

“Not a lot. It seemed like an unrelated suicide when it was called in until I got here and realized that it wasn’t. I don’t know how or why this kill was so different, but I know it was him.”

Liam’s instincts have never been wrong as long as Louis has known him so he doesn’t question his deduction.

“Where’s the body?” Harry asks, also realizing the absence of one in the usual place.

He and Harry exchange a look of surprise at Liam’s answer.

“Bathroom. Follow me.”

Louis was right to blame blood for the heavy scent of copper he picked up on the moment he set foot in this place since their third victim is quite literally bathing in a tubful of it. From there, Louis does a quick visual assessment, collecting every possible piece of information it can from what’s in front of him as Harry steps closer and comes to the same conclusions just as quickly.

“The victim is a male. Late twenties. Apparent suicide from slits on the wrist, but he didn’t make them. They were put there postmortem and probably by the same person who left the hand marks around his neck, meaning he was choked to death and it wasn’t suicide at all.”

The way all of that just confidently rolled off Harry’s tongue was like listening to a bloody symphony. Louis has to bite down on yet another inappropriate grin to hide just how proud he is when everyone in the room looks to him for confirmation, including Harry himself who has never made the pit of Louis’ stomach more weird and fluttery than it is right now when they lock eyes.

“Er- Thank you, Doctor. You’re absolutely right,” Louis says after a few seconds of mock consideration that Louis really uses to imagine what else Harry could say to give him chills like that.

“So, how do you think something like this happened, Lou?” Liam asks.

Louis doesn’t need to think when he already knows. “Same as before,” he explains. “Killer was let into the flat, probably under the ruse of some kind of date since he always brings wine. The first two were easy; women who probably didn’t notice when he slipped poison into their glasses during their meal, but this time his victim was a man who maybe did notice, or at least realized something was wrong and refused. Our killer is way past cocky by now having been successful at least twice before and he’s obsessive, so he couldn’t just leave it but now he’s been found out so he simply had to kill the man and quickly, but if not by poison, then how? Rhetorical question of course because the best thing he could think of was strangulation which caused some glaring problems for a victim who was meant to look like he killed himself, so he moved the body to the tub, slit the man’s wrists, and then left without realizing that bruises can take a while to show up, but they do show up even after someone has died, making his efforts pointless. He’s an idiot.”

“…Oh,” Liam blinks at him after Louis ends his very detailed and completely accurate analysis with a shrug. “Of course, Louis. Uh- Thanks for clearing that up. _In thirty seconds_.”

It’s silent as it usually is once Louis has pointed out the not so obvious. Even people who were collecting evidence in other parts of the flat have stopped what they were doing to gawk at him like he’s a freak, however, the only person Louis’ even looking at right now is his flatmate biting down on a proud grin of his own. Somehow, that feels better and even more rewarding to Louis than being right always does. And, fuck, does Louis _love_ being right.

“That’s all great, but do you actually have any idea who could be doing this?” someone who sounds incredibly annoying and Nick-like says from somewhere in the corridor where he thinks Louis can’t tell he has still been cheating on his wife.

“Yeah, Lou. Are we any closer to stopping this person?” Liam echoes sounding not at all like a prick. He’s just worried, and anxious to get their killer behind bars before he tries to correct his mistake and murders somebody else.

“We are,” Louis assures Liam and everyone else currently looking to him for answers. “I think I know exactly who we’re looking for and I can let you know for certain by the end of the day.”

*

“Do you really know who the killer is, Lou?” Harry asks when they get home.

“No, of course not,” Louis scoffs as he collapses into his armchair with his violin in hand for a bit of Bach to get his thoughts flowing before starting up with the shop journal again. He barely even makes it two measures into _Partita No.2_ when he opens his eyes to a very disgruntled looking partner slash flatmate who smells incredible for someone who hasn’t even showered today, but that’s just an observation. Just like the soft lilac base of his shampoo mixed with notes of fresh gardenia and coconut oils and something else sweet that he can't quite put his finger on.

“But, you said you did know,” Harry points out, just as miffed as the first time. “Why’d you lie?”

“ _Haz_ ,” he sighs, never having to actually explain himself or his choices to anyone before. “I only said that stuff because it’s what they needed to hear, alright.” And also because it wasn’t a complete lie. True, Louis has no idea who he’s looking for right now, but the name of the culprit is in that journal somewhere. “Uncertainty makes people nervous and frightened and none of those things have any business near a case like this,” he continues. “So, yes, I lie to them on occasion, but they also believe me whenever I do, which means they still have hope. I think that’s more important than the full truth sometimes.”

Harry still looks skeptical, but his eyes are softening by the second the longer he looks at Louis and he realizes he may have a point.

“Well. Has lying ever backfired and you _haven’t_ solved a case?” he asks with his arms folded over his chest the way Lottie often does whenever he’s done something ‘reckless’ like checking the condition of his firearms to make sure they’re in working order. Granted, he could probably not do that indoors, but she could also not boss him around like she’s the eldest.

“Oh, I _always_ solve the case, love,” Louis smirks. It’s what he does.

“And, have you ever lied to me?”

Louis doesn’t even have to think about that one before shaking his head. “No, Haz. Not once,” he promises which seems to bring Harry a great deal of relief. “And you?” Louis checks. “Do you lie to me?”

It’s mostly a rhetorical question since his green eyes are the most beautiful and honest pair Louis’ ever seen.  

“No,” Harry answers just as confidently. “Never.”

“Okay then, good. _Partner_ ,” Louis grins. “I’m glad we got that straight and we can now trust each other completely.” Not that Louis ever thought they didn’t. “Can I play my violin now please?” he asks making Harry fondly roll his eyes.

“Yes,” he relents with a stubborn grin. “ _But_ , only for a little while. We’ve still got a killer to catch by the end of the day. And, only if you promise to play a bit of Dvorak after Bach. He’s my favorite.”

“ _Yes, sir_ ,” Louis salutes him. A man who knows his composers is just as thrilling to Louis as a man who knows his way around a crime scene and a kettle. Honestly, where has this glorious human been all his life?

It’s hours later and almost sunset when Louis flips through the pages of the journal again and sighs when it doesn’t give him any new revelations about the people listed in it. Besides a few potentials who raised some small flags, most of what he and Harry have come across in this book has just been one dead end after another. The majority of the customers who went into that shop looking for contraband since this all started were women, which rules out three-fourths of their previous suspects because after that crime scene today Louis is certain now more than ever that their killer is a man. He just can’t figure out which.

However, there was this one that caught Louis’ eye a few days ago. A man called Arthur Manning, whom after a bit of digging, they found out is a real estate agent. A profession that fits the bill perfectly for someone with access to victims all over the city. It wouldn’t be hard for someone like that to move in and out of buildings unnoticed the way their killer has a knack for doing; even easier for someone who probably has a key for every lock. The only issue is that Arthur Manning’s last and only visit to the shop was nearly three whole years ago. A bizarre and lengthy timeline which makes Louis almost certain Arthur’s not the one they’re looking for.

_Almost._

“Hey, you,” Louis says when he gets up to find his flatmate stretched out on the sofa with his own list of suspects he’s getting nowhere with.

“Hey. Any luck?” he asks hopefully.

“Possibly. Don’t know yet. I need to do a stake out and break into someone’s flat first. Wanna come?”

“Oh.” Harry’s expression slumps a bit at that, but not to the point of total disinterest. “Er- Yes?” he answer/asks in that way of his that used to annoy Louis to the moon and back. Now, it just makes Louis smile just as far.

*

“But, what if this is the wrong place?”

“It’s not,” Louis rolls his eyes. “This is literally the only address listed for Arthur Manning for the past five years.” That extremely valid point manages to shut his flatmate up for a few seconds. Harry makes another defeated huff as he continues staring at the window five floors up and across the street from the thin line of trees they’re hiding in.

“ _Okay_ ,” he says eventually. “But, what if he just moved or something and now someone else lives there instead? I mean, what if he’s not even the killer, Lou?” In Louis’ opinion, the better question is what if he _is_?

Thankfully, just as Harry finishes voicing all his long-shot fears about committing his first B&E, a man with the same face as the one plastered all over the Happy Dwellings Agency website walks by the lit window they’re watching.

“Look! There he is. I think he’s leaving.” And sure enough, not even sixty seconds later does the flat go dark and Arthur Manning comes strolling out of the building’s entrance and down the darkening street. “This is our chance! Let’s go!” Louis says already halfway across the street before Harry gives another huff and then makes up his mind to follow along.

It doesn’t take them long to pick the lock once they make it up to the fifth floor. Or rather, it doesn’t take Harry long with Louis coaching him through each stage of breaking into a flat and then praising him for the upstanding moral criminal he is becoming. The man’s a fucking natural.

“So, what exactly are we looking for?” he asks once they’re standing inside Arthur Manning’s cluttered, yet relatively normal-looking living room. It looks just like theirs over on Baker Street used to, only without all the bullet holes.

“Look for anything that feels weird or somehow proves he’s our man. Pictures win us double points. Hard evidence from one of the crime scenes wins us the game,” Louis answers as he heads toward the bedroom because he knows from experience if there’s anything worth finding, it’s going to be kept there.

Louis searches through everything. Every drawer and typical place where someone might think to hide something of importance but all he finds are some old phone chargers, some loose change, and a bunch of dirty socks than never made it to the laundry bin due to poor aim. It’s not until Louis thinks to open the closet and notices a small wooden keepsake box that looks out of place amongst the tattered shoe boxes cluttering the top shelf.

There’s a lock on the outside of it that Louis quickly picks with the same hooked pin he just taught Harry to use. Louis knows what’s inside before he even opens it. Just it’s light weight gives its contents away immediately. As does the little glass vial lying in the center of it that’s an exact replica of the one he and Harry bought, except this one’s older. It’s edges cloudy with at least three years of residue from being encased in cedar wood, and just enough of the Tetrodotoxin missing from it to poison three.

It’s him.

Harry realizes they’ve got the right man at the same time Louis does, shouting from the kitchen that he’s found a blood-soaked shirt just as a door creaks open from what sounds to be the opposite end of the flat.

“Harry? You alright?” He doesn’t receive an immediate answer making him frown and poke his head out of the room to check on him. “Oh, there you are,” Louis grins when he spots his flatmate, but it soon fades to match the hard line of Harry’s mouth when he notices the owner of this flat who left it just minutes ago standing right across from them. His panicked eyes fall to the open box in Louis’ possession and then to the stained button-up shirt Harry is holding in his hands.

“Arthur,” Louis tries in a calm voice, but even just saying the man’s name has him taking a step back the way he came. “Now, there’s no sense in running. We already know and we’ve already found everything we need.”

Arthur just stares at them with defiance and Louis can practically hear the gears of his mind moving between fight or flight. He’s going to run which is fine because he won’t get very far anyway once they inform the police. Louis isn’t at all surprised when Arthur glances at the open door behind him and then takes off through it, but his heart nearly hammers in his chest when his partner drops the shirt he’s holding to chase after him.

“Haz, don’t! Let him go!” he yells, but his partner is already gone. Louis tears out of the flat towards the sound of a small struggle and heavy footfalls pounding through the corridor one after another. Louis catches up to them just in time to watch Arthur scurry into the stairwell only for Harry to be yanked along when he loses his balance trying to grab Arthur around the arm.

Louis’ blood runs cold as he listens to two bodies hit every step on the way down. When he finally makes it to the top of the stairs his stomach drops as if he was the one who just fell seeing Harry lying crumpled and unmoving at the bottom of them. Louis rushes to his partner, listening as Arthur’s injured and uneven footsteps continue down the rest of the stairs and out the back of the building, and Louis lets him. He’s too busy checking Harry over for a pulse and releasing a sigh of relief when he finds one that’s so big it hurts his chest as he cradles Harry closer to him. There are bruises forming all over his body but there are no broken bones as far as Louis can tell, thanking God Harry didn’t snap his neck as he digs out his phone to call Liam and get Harry an ambulance.

“You’re going to be okay,” Louis promises, hoping that’s true even if Harry can’t hear him. “You’re going to be alright, Haz. I’ve got you.”

*

“We’ve got every officer in the city on high alert. We’re going to find him,” Liam swears and Louis hears him, but what he said only registers when Liam gently squeezes his shoulder to pull his attention away from the ambulance parked across the street. “You can go see him now, you know? The paramedics said he’s a little banged up, but he’s okay, Lou.”

Louis had been so worried that at first the paramedics had to kick him out just so they could do their jobs. Liam forcing him to stay put was the only thing that kept Louis from hopping back up into that ambulance. Thankfully, he hasn’t been nearly as judgmental about Louis essentially losing his bloody mind.

“I’m so sorry for earlier,” he apologizes. “I thought he was really hurt. I’ve never been so scared in my life. I don’t know what the hell was wrong with me.”

“I think I do.” The way Liam’s knowing eyes go soft with a grin makes Louis feel uneasy. He’s used to always having the answers and everything making sense, and for some reason, with Harry, nothing ever does. “Go talk to him, Lou. You need to see that he’s really alright. It’ll make you feel better.” How Liam even knew that his stomach has been in knots this whole time will forever remain a mystery.

Louis waits outside the ambulance until the paramedics working on Harry hop down to graciously make room for him.

“Sorry about before,” Louis offers as they walk past in much calmer voice than he used earlier when he was panicked and spoke to them rather rudely.

“It’s quite alright,” one of them smiles just as knowingly as Liam. “It happens a lot more often than you’d think. You can visit him now and he’s free to go.”

He takes a deep breath before climbing into the cramped space of the ambulance and finally laying eyes on Harry sitting up in bed awake, alert, and most importantly alive. “Hey,” he grins at Louis, and just like that, the knots inside his stomach dissipate, causing relief to flood his chest instead. He’s never felt so happy to see someone with a dumb bandage taped to his forehead in his entire life. “I'm afraid that limp of mine might not be so psychosomatic for a few days,” he jokes, immediately taking it back when he hears Louis sniff and sneakily scrub a fist over his left cheek. “Lou?”

“You’re such an idiot, do you know that? I really thought something had happened to you,” he snaps, but Harry doesn’t seem offended as he nods with those beautiful clover eyes of his appearing warmer than ever.

“I know. And I’m sorry for scaring you, Lou.”

“Well, you did,” he bites back, stepping closer to Harry even though he’s angry with him, but he can’t help it. It’s like he just need to be near him. “You can’t just go chasing after serial killers and falling down fucking stairs. You could’ve really been hurt, Haz.” It makes him sick to even imagine it.

“I know. I was stupid, you were worried, I’m sorry for doing that to you, and- and I love you too,” he whispers as he wipes a new wet line away from Louis’ face. It’s not the first time Harry has ever touched him, but it is the first time it’s been so deliberate.

Louis searches the green eyes in front of him, feeling his brow furrow as he mentally runs through their conversation. “But- I never said-”

“But, you did,” he grins, and the next thing Louis feels is Harry’s mouth on his.


	5. Chapter 5

No matter how miniscule the distance, each time Harry pulls back to give Louis a bit of air, he just pushes forward again to find his lips as if they’re made of oxygen. It’s insanely flattering to be kissed like that, as well as a bit of a surprise coming from a man who prefers head nods to handshakes and physically stiffens at unexpected hugs from his sister or Niall Horan, however, something is different tonight. _Louis_ is different and is proving to be worth every bit of the wait it took for them to get here.

Harry must admit, he was worried after what he’d said and done back in the ambulance. All Louis could do was gape at him with wide eyes like he wasn’t quite sure he had really just been kissed, so Harry kept doing it. From the taxi ride home to Baker Street to the perilous journey up the stairs to their flat; gently coaxing Louis out of his head for once until the uninhibited man currently licking into Harry’s mouth without thought and walking them to his bedroom was all that remained.

The darkness of Louis’ room hides the small wince Harry makes as he steps out of his shoes, his right leg experiencing actual pain rather than the imaginary kind when he stumbles over them, but he ignores it for the feeling of Louis’ hands on him. Just like the dull little stabs he feels in every bruise on his body that brushes along the mattress when he and Louis lie back on it. He hisses a bit when their hips graze one another making his flatmate immediately pull back in alarm.

“Shit. I’m so sorry. Did I hurt you?” he pants, now looking Harry over like one wrong move might cause him to shatter. It’s sweet that he’s so worried, but also unnecessary. Harry has never been better.

“Nope. Not at all. I’m good,” Harry quickly assures him, pushing up to reconnect their lips despite the pain, except Louis doesn’t seem to be with him anymore once he does. His blue eyes are distant suddenly and pained by whatever nightmare keeps flashing through his mind each time he catches sight of the bandage above his temple and all his other bumps and bruises that weren’t there this morning, but they’re only minor injuries. Considering the distance he fell, they could’ve been a lot worse. Actually, Harry would say he came out of tonight pretty lucky, and in more ways than just one.

“I thought I lost you for a second tonight,” he whispers. “That you were really gone.”

“ _Hey_. None of that. The paramedics patched me up good as new,” Harry teases, though he can only imagine how scary that must’ve been. Just thinking about something like that happening to Louis makes his heart ache. “They promised I’m going to be just fine. No concussions or broken anything. I’ll just be spotted for a while like a giant Dalmatian or one of those cool-looking lizards,” he shrugs. “Completely normal. No big deal.”

Louis hangs his head to avoid snorting in his face. Harry’s just glad to see him smiling. “I guess you’re lucky I’m a dog person, then,” he jokes back making Harry feel like the luckiest person on Earth when Louis tilts his chin up to kiss him slow.  

Harry’s muscles give a slight protest when he widens his legs to bracket Louis in, but he pays it no mind, too wrapped up in the pair of hands gently feeling him over and the way Louis’ body is noticeably responding as a result. He’s growing hard between them which isn’t surprising considering the fast pace of this night ever since they realized Harry was in fact _not_ going to die, though, it feels like he might each time Louis’ hips stutter against him in an effort to maintain control. Harry doesn’t dare stop his shallow thrusts or interrupt their kiss as he blindly reaches out for the bedside table and yanks open the drawer. The whole thing nearly goes crashing onto the floor as a result along with all the weirdly bizarre shit Louis surely keeps in it, but he’s able to feel around for a bottle of lube and small roll of condoms.

Louis’ lips slow against his and then stop completely when he feels Harry pressing the items into his hand. He blinks down at them like it must’ve been some kind of mistake on Harry’s part, and just like when Louis couldn’t believe he’d been kissed, Harry grins up at him as his legs tighten their hold around his hips until Louis knows he wants this for them.

“Are you sure?”

“Absolutely,” Harry laughs. “But only if you want to.”

It’s not like Harry has missed the way Louis looks at him sometimes. Or the fact that his early morning yoga sessions have turned into quite the spectator sport, so he knows Louis is at least mildly interested. The heavy weight of his dick pressing into Harry’s lower stomach is a pretty good indicator that he has at least considered it too. And from the way he reaches down between them to squeeze himself tight, Harry’s almost certain he’s considering it right now.

“Tell me if anything hurts, like at all and we’ll stop,” he says, quickly stripping Harry out of his clothes. He takes his own off almost as an afterthought and then opens the bottle of lube with far less grace than someone whom Harry has seen slice a grape tomato with the blade of a Wakizashi sword in a single swing. His slick fingers lose their grip around the bottle twice causing him to dribble lube down the inside of Harry’s thigh and onto Harry’s green blanket which now mysteriously lives here instead of in Harry’s bedroom. Not that he really minds the mess that’s only going to get worse in a few minutes anyway, or Louis casually stealing his things.  

“F-Fuck. Sorry,” he mutters as he tries to clean it up and only succeeds in smearing it everywhere.

“Nervous?” Harry chuckles while watching him fumble. Usually, Louis is so on his game that nothing in the world can touch him. He’s in a league all on his own and Harry loves that about him, but it’s also fun to know that at the end of the day he’s just a typical boy whose brain short-circuits at the promise of sex.  

“Shut up,” he smirks which only makes Harry smile more because he’s never seen Louis blush before. “It’s not every day I get to be in bed with someone like you, you know? You’re gorgeous. I’m sure everybody spills lube when they’re in my position.” It’s not every day that Harry gets a privilege like this either. He’s just a little better at hiding the fact that his heart has been racing since they first kissed.

The deep breath Louis takes before he begins tickles Harry’s navel on the exhale, giving birth to a million little goosebumps that fan out all over his body when Louis sinks his fingers inside of him. There are no more visible signs of nerves as he opens Harry up with the careful skill and precision that Louis puts into everything he does.

“You alright?” he asks when a particularly accurate press of his fingers sends Harry’s taut muscles into convulsions. It causes a bit of a sting in all the places he’s bruised up, but that just adds to the pleasure of it each time Louis brushes over his spot. All Harry can do is nod in answer to his question, his brain momentarily turning to static when Louis adds a third finger and gives his tip an experimental lick with his tongue. Louis sinks his entire mouth down over it when he finds he likes the taste, adding shivers on top of the way Harry’s body was already shaking.

“Lou, the condom,” Harry pleads through clenched teeth a minute later, his chest slick with sweat already just from the effort of not coming down the tight throat encasing him.

Louis pops his head up with his lips cherry red and the darkest shade of blue Harry’s ever seen ringed around his pupils. He uses the back of one of his dirty hands to wipe his magnificent mouth and Harry can’t make himself stop staring.

“Turn over for me?” he says, smiling when Harry immediately does so without question. “Eager?”

“Yes. Shut up,” Harry chuckles over his shoulder, now feeling a bit nervous himself as he watches Louis prep himself.

He gets chills as Louis’ positions himself, counting every new dip of the mattress his knees create until they’re bracketing Harry’s on either side and they’re flesh to flesh. Harry lies as still as the adrenaline pumping through his veins will allow, breathing in deep when he feels Louis’ tip at his entrance and his stuttered breaths just below the nape of his neck.

“Ready?” Harry nods, bracing himself for the initial stretch of Louis pushing into him but all he feels is a pair of soft lips pressed to his shoulder. “I won’t hurt you,” he promises. “I’ve got you.”

Surprisingly enough, Louis manages to keep his word when he slides his hips forward flush to Harry’s bum. He takes it slow at first, just breathing Harry in as they both adjust and then he’s gently pulling out just to push back in, fucking Harry in long even strokes that have Harry sighing against the mattress.

“That’s _so_ good,” he says, listening to his own breath catch in his throat each time Louis slowly sinks back into him. A long exhale skates across Harry’s skin when Louis presses his front along Harry’s back to bring them closer. He settles into their rhythm, periodically pushing in so deep that Harry’s breath is stolen completely, but it feels fucking amazing.

He picks up the pace after a while, starting a little fire at the pit of Harry’s stomach that sparks and fans with each deliberate roll of his hips. Louis hasn’t said much since they began, but Harry’s starting to think it’s more so because he can’t rather than he doesn’t want to. His grip is shaky where it’s braced at Harry’s waist and his breaths go still each time Harry tries lending a hand by pushing back onto him.

“Sh- Shit, Haz,” he stutters when Harry comes up on his knees a bit to take him deeper. It gets Harry exactly what he wanted, encouraging Louis to shift with him and chase the tight heat surrounding him.

Harry reaches out for something to hold onto when skin starts to slap against skin, sinking his teeth into his bottom lip as he’s rocked into the mattress. He’s squeezing the sheets so hard that his fingers ache around them, but he doesn’t let go until the pounding subsides and Louis asks him to lie on his back instead.

He’s all sweaty and flushed from the chest up when he settles between Harry’s legs again and he hikes them up around his waist. It’s much easier for him to push in this time, swearing aloud as Harry takes every inch of him in one slick motion. Until now, Harry hasn’t been able to see Louis’ face and all his reactions to being inside of him. All he had to go on while lying on his stomach were the sounds Louis would make or changes in the rhythm of his thrusts, but seeing his eyebrows scrunched high over his nose in ecstasy and his jaw hanging open from nothing but the feel of him somehow tops it all.

They share a kiss when Louis lowers himself so far that their damp skin slides everywhere they’re touching. Slowly, he starts to roll his hips again, speeding up and breaking their kiss when Harry cries out. It’s like electricity dancing at the bottom of his spine when Louis finds his spot again, so powerful that he wonders if Louis can feel it too from the deep strokes he’s pushing into him.

“I’m close,” he admits, though the slight trembling of Louis’ lips hovering just over his gave him away seconds ago.

Harry clings to him, welcoming every shuddered thrust he makes and allowing the pit of his stomach to coil in on itself until the first wave of ecstasy hits him like a punch to the gut that leaves him breathless. It’s quickly followed by a second wave, pleasure ruthlessly tearing through him as he gasps for new air so hard his chest burns, but all he can focus on is the stuttered rhythm of Louis’ hips when he can’t hold off any longer either.

Louis jerks above him and comes with a desperate moan turned whine into the crook of his neck. His body continues actively chasing the heat and feeling of him until he’s completely spent. When he finally stills, Louis lies back on the pillows to catch his breath, his heart audibly skipping a beat when Harry follows him and pillows his head on his chest. They’ve never cuddled before. It’s possible Louis is new to the whole concept so Harry helps ease him into it by locking one of Louis’ arms firmly over his shoulders and entangling their legs so he can’t escape. Harry keeps expecting for him to pull away or at least tense up, but all Harry gets instead is a warm kiss to the forehead and their free hands laced together.

He’s a natural.

 

_Saturday. 8:53am. ~~221b Baker Street. London~~. Medic Tent C. Kunduz, Afghanistan._

Harry steadies his fingers around the pair of forceps in his right hand, using his left to keep his patient from squirming so he can remove the rusty piece of shrapnel stuck in his thigh. It’s difficult to concentrate with all the commotion going on just outside their camp. An early morning attack a few miles away left dozens of soldiers and civilians injured, and the gunfire has been moving closer to them ever since.

“I know it’s difficult right now, but I need you to try and stay still,” Harry tells the soldier who jumps at every shot that rings out over the desert sand. All he’s doing is making the wound worse, wedging the shrapnel further into his skin, but Harry can’t blame him for being on edge.

The sound of a gate busting open somewhere and panicked voices suddenly ordering people to evacuate distracts the man long enough for Harry to remove the jagged piece of metal from his leg in one quick yank. There’s no time for celebration, though, almost as soon as it’s out shots start firing a few yards from their tent.

“What are you doing? We have to get out of here!” the man says watching Harry claw through his supplies. Harry agrees with the man completely. Most of the camp has probably already fled like they need to, but this soldier’s leg isn’t going to get him very far with a giant slash in it not to mention the fact that it’s practically screaming infection with how filthy it is. Stitches and a heavy round of antibiotics would be best, but all Harry can find on such short notice is disinfectant spray and surgical tape.

“Just let me close it up! I only need a second!” Harry promises just as one stray bullet pierces a hole near the ceiling of his tent and another tears straight through his right thigh, leaving the muscle and tissue there feeling like they’re on fire before he collapses to the ground.

When Harry opens his eyes, he’s surprised to find a warm bed beneath him instead of the hot desert sand that still haunts him sometimes at night. It’s Louis’ bed, so he’s still slightly confused about where the hell he is, but at least it’s not a fucking war zone. Nightmares about that day used to plague him every time he closed his eyes, but they’ve been better lately. He has been so busy with Louis and the case that he hasn’t had time to think about anything else. Not that he considers that a _bad_ thing. Not at all. Meeting Louis was the most fun he’s had in over a year.

Harry stretches and frowns when his body doesn’t come into contact with anyone else’s, but the air is heavy with the scent of syrup and bacon wafting from the kitchen so his missing bed partner must be there too. He locates his pants on Louis’ floor and pulls them on, raising an eyebrow at the strange clock he passes on his way out the door that looks to be a bunch of colorful spheres until Harry realizes they’re polyatomic molecules.

He’s still wearing a grin when he gets to the kitchen, feeling it widen into a smile when he finds Louis there carefully arranging two plates of food on a little tray. Louis doesn’t notice him right away as he putters around the kitchen grabbing the things he needs while the kettle warms on the stove. He pours the water over two bags of Yorkshire once it’s ready, and even grabs the sugar, hardly even making a face when he places it next to what could only be Harry’s mug since Louis wouldn’t dare add it to his own.

“Is all that for us?” Harry asks, causing Louis to jump at the sound of his voice.

“Well, it _was_ before you went and scared the living shit out of me. Jesus,” he snorts. Harry moves closer to the tray he didn’t even know they had, grinning at the fresh pancakes piled high on their plates. “Um, I would have brought everything to you…I was just going fix some tea first. Also, we’re out of eggs so I thought I’d try something different. I wasn’t sure if you like pancakes or not. I’ve never seen you make any but I know you love bacon, so.”

He finishes with a cool shrug, but he’s watching Harry closely, studying every twitch of his face for a sign of approval. Harry could tell him how pancakes are his favorite even though he rarely has time to make them, or how even though he kind of ruined the surprise, nobody has ever even thought to bring him breakfast in bed. He could, but the kiss he steals from Louis’ slack lips feels like a much better thank you and show of his appreciation.

“Okay. I take it you _really_ like pancakes,” Louis laughs letting both stacks go cold along with their tea to kiss Harry back. 

*

It’s been hours since he and Louis identified the killer and _nearly_ caught him. Harry still can’t believe how close he got. He also can’t believe Arthur Manning is still out there somewhere hiding. _Running_ ; possibly so far away that he’ll never be caught and those people’s deaths will never be answered for. Louis doesn’t think that though. He seems to have complete faith that Arthur Manning is right under their noses, biding his time.

His flat has been under twenty-four-hour surveillance in case he goes back there, which, according to Louis means that he never will. That gave Harry some peace of mind when he heard that, because if Arthur is kept away from the Tetrodotoxin that means the killing is over. But, again, Louis begs to differ claiming that at this point he won’t be able to stop. He’ll just find another way.

There’s not much they can do besides wait. Either for Arthur to get restless and try to redeem himself with a fresh murder, or for the police to finally catch him and bring him in. Harry’s hoping for the latter that afternoon when he settles down at the small desk in his bedroom with his laptop open to his medical blog he hasn’t looked at since leaving Afghanistan. He used to update it religiously. Every week he’d sit down and tell the world all about his journey and his experiences helping people and giving hope in a place where there seemed to be none. The last entry was made months ago. Just one week before he was injured when he was feeling so proud to have just signed on for another six-month stint, and then he blinked and he was back in London traipsing through crime scenes with his new flatmate and happily falling in love with him.

Harry hasn’t done any recent life-saving or bullet extractions to blog about, but he could still write. He isn’t working in war zones anymore, but he has been on a pretty great adventure. One that’s still in full-swing if the sound of a violin screeching to a halt and a pistol firing into the living room wall is anything to go by. Perhaps he should blog about _that_.

He closes his laptop and heads to the living room, fondly shaking his head when he hears Louis sigh from his armchair the way he has been doing all afternoon since Liam’s not-so-stellar update on Arthur Manning about an hour ago. He guiltily peeks around the back of the chair when he hears Harry coming.

“Adding to the décor again I hear,” he teases.

“I was just…checking to make sure it still works…” he mumbles when Harry grins down at him at the antique weapon resting in his lap. “I need it. It helps me think sometimes,” Louis amends before giving a loud huff. “Alright, I’m sorry I fired the gun, it’s just- _why_ hasn’t he been found yet? I mean, honestly. We’re closing in on twenty-four hours here and not a fucking peep?! You’ve seen his crime scenes. We’re not exactly dealing with a mad genius here so what the hell is he up to?”

Harry can empathize with his rant. He expected to hear something by now as well and he is feeling a bit restless too, just not indoor-target-practice-restless. But, there are other ways of relaxing and letting off some steam.

“I knew he would run,” Louis continues as Harry kneels down and carefully removes the gun from his lap. “I fucking knew it the moment I saw him, I just didn’t think he’d actually be any _good_ at- Wait what’s happening?”

“Nothing,” Harry blinks up at him as he pushes Louis’ t-shirt up to get at his drawstring. “I’m listening. Please, go on.”

Louis flounders for words while Harry tugs his joggers down around his semi. Harry strokes him at the base a few times before sinking his mouth down over it, and suddenly Louis is struggling to breathe properly let alone overthink. Louis’ head falls back with a deep moan that stretches on for so long that Harry pulls off to make sure he’s alright.

“I’m sorry. You were saying?”

“Nothing. _Fuck_ ,” Louis sighs, letting his fingers tangle at the roots of Harry’s hair when he resumes swallowing him down.

Call it a strong hunch, but Harry would say he’s definitely not thinking of Arthur Manning right now. In fact, he doesn’t hear even a mention of the man for the rest of the afternoon.

 

_Sunday. 5:56pm. 221b Baker Street. London._

“Lou, do you know that you wouldn’t even _need_ a flatmate if you just authorized even half of these payments? You could afford this place on your own twice over.” Not that Harry’s saying his epiphany about Louis’ finances should suddenly encourage him to live here alone. He’s just stating facts.

Harry didn’t even mean to stumble upon all this stuff when he asked to borrow Louis’ laptop because he was too lazy to go get the charger for his own. He was simply signing Louis out of his email account so he could sign himself in when he noticed all the multi-figure cheques just sitting there untouched.

“Lou? Did you hear me?” Harry asks from the sofa, blinking up from Louis’ fortune a minute later to find Mr. Moneybags himself standing right in front of him. “Oh. There you are. You do realize you could buy this flat? Possibly the whole building. You could probably retire from being a detective tomorrow.”

Harry turns the laptop around so Louis can see his calculations and he looks mildly interested. Mostly, just nervous. Which, to Harry, is mildly concerning.

“So, I was going to do this thing later. Wasn’t sure if you’d like to come with me?”

“ _Okay…_ ” Harry chuckles to himself. “What thing? Another B&E?”

“Uh, no. Dinner, actually,” Louis says quietly. “Well, we’ve been stuck in this flat for days and it’s not like anything can really be done about Arthur Manning until he’s found, so while we’re waiting I figured we could maybe try that restaurant over on Asher Street that everybody’s always going on about. O-Or not,” he hurries to say when Harry doesn’t give his rambling an immediate response. “We could do something else entirely or just stay here. I only wanted to see what you thought.”

Harry shuts the laptop, unable to keep the grin he’s wearing from spreading across his face.

“Louis. Are you asking me on a date? That weird thing where two people who like each other go out and have fun?”

Louis seems to consider all the implications of the word before nodding with an astounded ‘ _Yes_?’ followed by a confident, ‘I am.’

“I’d love to,” Harry says, his quick answer obviously coming as a shock to Louis when he blinks in surprise.

“Yeah?” he grins. “You would?”

“Of course. What time should I be ready?”

Louis sneaks a glance at the clock before meeting his gaze again. “Er- I can make a reservation for eight. Would that work?”

That gives Harry over an hour to pick an outfit and get ready. “That’s perfect,” Harry smiles before standing up to press a quick kiss to Louis’ lips. “Meet you back here at seven-thirty?” Louis still seems a bit unsure as to how exactly this all came about when Harry leaves him there to go get dressed, but he’s cute looking so lost in the middle of their living room. 


	6. Chapter 6

The sleeves of Louis’ shirt ride up his forearms a bit when he pulls his dark grey sweater over top of it. He spends a whole five minutes trying to right them again and also fixing the section of his hair that just got ruffled in the process. Usually, he simply leaves his messy hair that way, and he has never bothered with the sweater his sister bought him three Christmases ago because it’s too nice to wear to a crime scene or to St. Bartholomew’s. He also doesn’t ordinarily pace around his bedroom for over half an hour getting up the nerve to ask someone to eat dinner with him, but lately he’s doing all sorts of new and strange little things when it comes to Harry. Maybe he really does love him after all.

He checks himself over in the mirror once he’s all straightened out and then consults the molecule clock hanging on the wall. It’s already five past and Lottie swore she’d be here by seven. Thankfully, his phone vibrates with a new message announcing her arrival as requested just before he was about to call and bug her again.   

There’s music playing when Louis tiptoes out of his bedroom. The deep tones of his flatmate’s voice singing along to some eighties pop playlist echoing through the flat as Louis hurries to go meet his sister. The front door creaks a bit when he opens it to let Lottie in, but luckily, Harry is so busy harmonizing with Madonna that he doesn’t hear a thing.

“Sorry I’m late,” she whispers when Louis ushers her in with one finger held over his lips. She has the bouquet of wildflowers he begged her to pick up for him protectively cradled in one arm, handing them off to Louis with an eyebrow raised in interest. “Here are your flowers. What on Earth was so important that you needed them tonight?”

“I didn’t have time to go out. And, they’re not for me. They’re for Harry. We have a date,” he explains when Lottie just blinks at him. “People do that, right?” he checks. “First date flowers are a thing?” At least that’s what Louis has been led to believe all these years. Though, it’s not like he has any real-life experience with this sort of thing whatsoever, so he could be- dare he say it- _wrong_.

His sister looks him over in astonishment and near disbelief, taking in the smooth cut of his jaw that’s now visible thanks to a close shave and the grey sweater she recognizes immediately, the combination of both softening her expression to one that looks oddly similar to pride. “Yeah, Lou. People do that,” she smiles. “Flowers are a nice touch for any occasion. Especially first dates.”

Louis thought so. And even if flowers weren’t typical he’d still like to give some to Harry. He loves them. Everything he owns smells of fresh blossoms and springtime even down to his shampoo.

“Where are you taking him?”

“Dinner hopefully. I tried to make reservations too late at Vine so we’re on standby, but we can always go someplace else if that doesn’t work,” he shrugs. Next time, Louis will know better than to ask Harry out on a random, impromptu date, less than two hours prior to it commencing.  

He should’ve seen it coming from the incredibly sappy gleam in Lottie’s eyes, but she surprises him anyhow just before she leaves. “Aw, come here, you,” she says wrapping him in a tight hug complete with a kiss to his clean-shaven cheek. And usually he’d make a fuss about personal space, but she did pause her evening to help him, so he allows it. He even hugs her back. “Good luck tonight. And I love you,” she tells him before sneaking out into the corridor just as quietly as she arrived. “Oh, and let me know how it goes? I’d love to hear all about it sometime.”

“Er- Okay. I will. I’ll call you tomorrow,” he promises, making concrete plans to chat with his little sister for the first time ever. “And thank you. For the flowers. I’ll pay you back.”

“Don’t worry about it, and you’re more than welcome. Harry’s going to love them.”

He sure hopes so.

Louis is ready and waiting by the sofa at seven-twenty-nine when the music stops playing from Harry’s room and his door swings open a minute later. He’s smiling from ear to ear when he rounds the corner in pair of black slacks and a matching jacket. His face only brightens more when Louis hands him the bunch of wildflowers that resemble the tiny sheer ones embellished down the front of his shirt.

“Where did these even come from? These are gorgeous. They’re beautiful,” he gushes as he sniffs every daisy and sprig of lilac under his nose. They’ll also be dead in a week, hence the whole concept of giving flowers as a sign of affection seems a bit morbid to Louis, but if they make his flatmate this happy he won’t rain on his parade. “Thank you, Louis.”

Louis notices his stomach fluttering like mad when Harry presses a kiss to his jaw on his way to find something to put them in. After all this time, he finally realizes that peculiar sensation is what everyone calls having butterflies. Harry comes back with one of his tall beakers instead of the non-existent vase he must’ve realized they don’t own, but he seems thrilled with his flowers being displayed in it just the same.

“ _There_ ,” he beams as he sets them by the window to admire them. “They’re perfect.”

“Are you ready to go?” Louis asks once Harry’s finished arranging the blooms the way he likes. “We should leave if we’re going to make it by eight.”

“Oh- Almost,” Harry says, coming to stand next to him and gently slipping his hand into Louis’ with a grin. “ _Now,_ we’re ready.”

*

Louis has spent the last two days referring to Arthur Manning as the daftest and most idiotic person on the planet but he feels as though he now owns that title when they show up to Vine and find that their standby reservation is useless. No one with a real reservation for the hot new restaurant in town called to cancel like Louis had hoped, so now they need a plan B. Which Louis doesn’t really have.

“Shit, Haz. I’m sorry,” he offers as they step aside to make room for the other, smarter people who actually took time to plan their evening.

“It’s alright. I don’t mind,” Harry shrugs, looking genuinely unbothered. “We can just go eat at wherever is closest. I believe we passed a lovely McDonald’s on the way here,” he jokes.

Louis snorts at that, certain they can at least find a place nearby that has real silverware. “Come on. I think there’s an Italian place down the street,” he says, but just as they turn to leave, none other than Niall Horan is standing there blocking their path.

“Louis? Harry?” he frowns, looking almost convinced he’s seeing things. “What are you two doing here?”

“Uh, we were actually just leaving, so not much I’m afraid.”

“Oh,” Niall nods, now studying them with even more curiosity when he notices their clothes and how closely they’re standing next to one another. “So…is this like a work thing, or?”

Louis should just tell him that he and Harry are here together but he feels weird saying it. The way Niall and his own date are watching them makes him feel weird saying it. “Er- Well, no. Not exactly-”

“We’re actually just having a date night,” Harry explains, taking Louis’ hand in his and instantly alleviating the tension he could feel building in his chest. “Or at least, we’re trying to,” he laughs. “We didn’t make a reservation for here so we’re going to another restaurant.”

Niall only looks stunned by this news for a moment, gazing between the pair of them and their linked hands until he’s grinning just as big and proud as Lottie did earlier tonight. Louis has never really had friends in the technical sense, but he guesses Niall Horan is as close to one as he has ever gotten, and right now he looks genuinely happy to hear that. Thankfully, he’s able to resist the urge to affectionately squeeze him to death about it, and Louis is genuinely happy about _that_.

“Well, that sucks, but you guys should still stay. We have reservations so I don’t see why we can’t all have dinner together,” he suggests with a smile. “Amanda and I don’t mind making it a double date night if you two don’t.”

That’s an incredibly kind gesture for someone who spends a good portion of his week sharing his lab equipment with Louis and putting out fires that _Louis_ of course caused. It could be nice to have a conversation together without an extinguisher present or a dead body on the table.

“Uh, well, if you’re sure?” Louis checks after a quick glance at Harry who already looks sold on the idea.

“Of course,” Niall beams. “It’ll be fun.”

It’s nearly two hours later when Louis looks around the dinner table he’s sat at and realizes that Niall’s prediction was completely right. Prior to this evening, if someone had asked Louis to describe his idea of hell on bloody Earth this would’ve been it, but after a couple of glasses of wine and with Harry by his side, he can honestly say that he is having fun.

When he’s not kicking Louis out of his lab and swearing to change his access code so he can’t get back in, it turns out Niall is actually alright. And his girlfriend, Amanda, a physician who also works St. Bartholomew, has a lot in common with Harry and hangs on every word he says about his time working in Afghanistan. She’s also quite intrigued when their conversation inevitably shifts to what Harry has been doing ever since then, leading them to discuss Louis’ favorite thing in the whole world; tracking and catching criminals.

“That’s so terrible,” Amanda frowns after he and Harry simultaneously recount the night Arthur Manning unfortunately slipped through their fingers. “So, where do think he is now?”

Louis wishes he fucking knew. He hates to admit that he doesn’t.

“Well,” Harry begins. “No one knows for sure, but if anybody can figure it out, it’s Lou. He’s amazing at what he does. Truly the best,” he answers her, giving Louis’ hand a proud squeeze where it’s resting on top of the table. And, it could be the alcohol warming him up and making him feel tingly all over, but Louis’ pretty sure it’s just Harry and the way he smiles at only him when they lock eyes. And, although this night has been great and more fun than he could’ve guessed, suddenly, all he wants is to go home and to take Harry with him.

*

It’s barely even thirty minutes later when Harry has his legs so tightly wrapped around Louis’ waist that he’s having trouble breathing properly as he rocks inside of him. Louis’ grip tightens around Harry waist as well as the arm of the sofa just above Harry’s head, watching as Harry’s head comes within inches of hitting it with every thrust Louis pushes inside of him. The sounds Harry makes as he moans his name sends cool little chills down his arms. Having sex with Harry is all he wanted from the moment they left Vine and clearly the feeling was mutual since Harry had them naked and panting on this sofa the instant they walked through the door, but even with all the desperate swearing and the blunt nails digging into his back he can’t get their conversation from dinner out of his head. Where the fuck is Arthur Manning?

Harry presses up to kiss him, licking into his mouth and biting at his lips in a way that leaves his skin ablaze. “You okay?” he breathes, gasping when Louis nods and doubles his pace in answer. He’s fine; more than, and Harry sure sounds like he’s having a blast but the fact still remains that their killer is out there hiding somewhere and doing a hell of a good job of not being found. It’s ridiculous. There have been officers camped outside his place for the past two days as well as the residences of all the flats he’s sold in the past six months just in case he wants to try again, and nothing. He hasn’t returned home and he hasn’t tried to move on from his blunder with his last victim. Serial killers don’t just stop being serial killers. They have to best themselves. They need to move on to bigger and better things to prove they’re untouchable, but what if the issue here is that Arthur _can’t._

Louis gasps aloud when all the thoughts that have been whirring around inside his mind all this time finally land on the answer; the reason why he can’t think ahead to Arthur’s next move. It’s because he’s still stuck on his last one.

“What?” Harry asks, eyes flying wide when Louis suddenly freezes above him. “Shit. What happened? Did you already-?”

“I know where he is!” Louis answers, enjoying the immense pleasure that comes from being right… and also from being balls deep inside his partner, because that’s nice too.

“ _He,_ _who_?”

“Arthur Manning! I know where he is! I mean, technically I guess I’ve know this whole time I just never thought he’d actually go back there.”

“Back where?” Harry frowns.

“The last crime scene.” Psychopaths always go back to reminisce on all the horrific shit they’ve done, but Arthur doesn’t want that. He wants to try and figure out what went wrong. That, and a dead man’s flat is the only place in the city he could go where there are no cops looking for him, but that’s certainly about to change.

Louis reaches for his phone tucked in the back pocket of his slacks lying on the floor and sends Liam a text to let him know where to finally pick up their killer. “They’re going now to arrest him,” Louis sighs in triumph, feeling that familiar thrill roll his spine from winning the game. “We’ve got to go meet them. Let’s go,” Louis says but he doesn’t get very far with the way Harry’s thighs tighten around him and the very pointed look he fixes Louis with.

“Um, you solved the case and that’s beyond brilliant. Seriously, cheers. I’m proud of you, but aren’t you _forgetting_ something?” Or perhaps, a _couple_ of somethings Louis gathers when Harry looks between them where they’re both still connected and both still achingly hard.

“Er- Right. Yes. You’re completely right. Liam’s probably got it well under control until we get there. My mistake.”

That puts a happy smile on Harry’s face, but not quite as happy as the one he sports when Louis kisses him and resumes fucking him into the sofa cushions.

Louis could tell that he’d been right and Arthur Manning was caught when they pulled onto Sterling Street to find it bustling with officers and reporters, all hailing the end of the massive manhunt that’s been going for days. The killer is no longer there by the time Louis and Harry arrive. He’s long gone, handcuffed and off to spend the rest of his life behind bars, and Louis couldn’t be more thrilled.

“We never would’ve caught him without you, Louis” Inspector Payne tells him later when everyone has started to clear out. “I don’t know how you do it, but I’m glad you solved another one. I can’t thank you enough for your help.”

“It was nothing. Just another day at the office,” Louis shrugs, grinning when Harry playfully elbows him for his modesty.

The action doesn’t go unnoticed by the inspector who looks at them with furrowed brows.

“You two are dressed quite nice tonight,” he says, kindly choosing to not comment on the state of their hair. “And, Louis, since when do you shave before coming to work?”

“Uh, I don’t,” Louis chuckles as he slips his hand into Harry’s. “I hadn’t planned on working. Haz and I had a date tonight. We left and came straight here.” That’s not exactly true. Date night was still in full swing when he figured out where Arthur Manning was hiding, but details aren’t important. Not with Liam looking so happy for them that his eyes are nearly closed from being so crinkled. Perhaps Louis has more friends than he thought.

“That’s great to hear, you two.” He claps Louis on the shoulder and gives it a proud squeeze. “I’m happy for both of you,” he tells them, still smiling when he heads to his car after wishing them a goodnight.

“You saved the day,” Harry grins when they’re left alone in the middle of the pavement.

“With your help of course,” Louis reminds him. Louis likes to think he can do anything, but he’s not sure he could’ve pulled this one off alone. And when he kisses Harry to thank him, Louis’ certain that he wants his partner with him from now on.

 

_Two Weeks Later. 11:36am. 221b Baker Street. London._

Harry reads over the last sentence he typed, happily finding no errors or mistakes in his personal account of the Arthur Manning case. His blog has been inactive for months, but he feels that same cathartic satisfaction as he did in Afghanistan when he hits post and updates his blog with a new kind of adventure. 

When it’s up, he sits back from the desk to admire it, grinning when he feels someone lean down to read over his shoulder.

“ _Toxic Realty Properties: Homes and Flats to Die For_. Clever,” Louis chuckles, smacking a kiss to Harry’s jaw. “I love it.”

“Thanks, babe.” Hopefully, his readers will love it too. Assuming he even has readers anymore after disappearing on them for so long, but according to his visitor counter in the bottom left of his screen, several people have already gotten a head start.

“I was going to go make some tea. Want some?” Louis says after the counter hits triple digits.

“Please,” Harry nods as Louis heads to the kitchen, still watching in amazement as the numbers climb faster than they ever did when his blog was strictly medical.

His inbox which has only ever received a couple of messages in the past, now has half a dozen. He goes to open the first one, freezing when his phone vibrates on the desk at the exact same time as Louis’, the amplified sound making his boyfriend poke his head out from the kitchen with his lips curled up into a wicked grin.

“This is it! That’s our next case,” he says, and sure enough when Harry flips over his phone there’s a message there from Liam about a high-profile burglary heist from Buckingham Palace. Louis doesn’t even wait to hear the rest of it before he’s excitedly running through the flat to find his shoes.

“What about the tea?”

“Some idiot just robbed The Queen in broad daylight and Liam Payne has no idea how,” Louis smiles like it’s the best thing he’s ever heard. “ _Fuck_ tea. Let’s go.”

Harry hops up to leave with him, closing his laptop on his blog just as the counter hits five-hundred. He wouldn’t mind staying to see just how big of a response it’ll get, but something tells him he’ll have a fresh update soon enough. _A Royal Robbery_ perhaps? Or maybe, _The Crown Jewel Fool_? Harry only gets to contemplate titles for a moment before Louis huffs and begins impatiently pulling him along like a two-year-old.

“ _Let’s go or I’m leaving without you!_ ”

He wouldn’t, but Harry doesn’t call him on it, finding his enthusiasm far too cute to chastise.

“Yes, dear,” he smiles. “Right behind you.”

\------------------

**Notes for the Chapter:**

> I had entirely too much fun writing this! Hope you enjoyed reading it <3
> 
>    
> [ rebloggable fic post](http://all-these-larrythings.tumblr.com/post/170831889176/a-study-in-love-24k-by-rearviewdreamer-louis)

**Author's Note:**

>  
> 
> Thanks so much to Tabby, the single best beta in the world, and also to Larrysunrays, without whom this fic would not be a thing <3 <3


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